Minecraft in Skyrim, Mario in Elden Ring: how AI-built game mashups took over PC modding in a week

Over roughly a week in late September 2026, a new kind of mod swept across gaming social media: one game running inside another. Steve from Minecraft swinging a sword at Lands Between enemies in Elden Ring. Super Mario bouncing off Margit's hammer. Skate 3 tricks in the middle of a Modern Warfare 2 map. Skyrim turned into a block-building survival sandbox. The clips pulled in millions of views, the repositories started appearing on GitHub, and the argument about whether any of this is good, real or even legal started almost immediately.

This is the full picture: who made what, how the tricks actually work, which mashups you can download today and which exist only as video, what the AI tools did and did not do, and where this could realistically head.

What happened, in order#

The wave is easy to date because it moved so fast. Modder chasm posted a skateboarding mod for Call of Duty: Modern Warfare 2 in the last days of September. On 29 September, Tobyn Jacobs showed Minecraft running inside Elden Ring on X and YouTube. The next day, Deltaroo showed Mario fighting Elden Ring bosses, and Rehan Sheikh, publishing as rehan-remade, released an open-source toolkit called Universal Modder that gives Anthropic's Claude Code a structured workflow for modding PC games. By the start of October, gaming sites were running explainers, and by 6 October the trend had its own name in modding circles: passthrough modding.

According to a VGTimes breakdown of the trend, the biggest clips were seen tens of millions of times: Minecraft in Elden Ring at about 22.5 million views, the skateboarding Modern Warfare 2 mod at about 7.3 million, and a Mario-versus-Margit clip at about 5 million. Treat those as the outlet's figures rather than ours, since view counts move by the hour, but the scale is not in doubt.

It is not code fusion: how mashups actually work#

The phrase going around, "merging two games", is slightly misleading. Nobody has welded Minecraft's source code onto Skyrim's. What these projects do falls into three techniques, and knowing the difference tells you what to trust.

1. Two games, one bridge (passthrough modding)

This is the approach behind the headline mashups. Both games run on the same PC at the same time. A small bridge program passes data between them every frame: the camera position, the ground under the player, events such as explosions or hits. One game's image is then stitched into the other's frame, with depth information so objects block each other properly.

VGTimes describes one example in detail: in the Minecraft-in-GTA 5 project, Minecraft sends around 160 "ground probes" to GTA 5, and GTA sends camera and player data back. The host game is what you see and walk around in. The guest game quietly runs the rules.

SkyCraft, the Minecraft-in-Skyrim mod, works this way. Its documentation says neither game is rewritten: Minecraft runs its own game logic hidden in the background, and Skyrim keeps running its world, NPCs, quests and saves. A Skyrim plugin written in C++ (using SKSE, the Skyrim Script Extender) and a Minecraft mod written in Java (for the Fabric mod loader) talk to each other through shared memory, following a documented protocol.

2. One game rewritten from scratch

The second approach rebuilds a game's rules in a new engine and loads the original assets from your own copy. VGTimes says this is how the Modern Warfare 2 skateboarding mod works: a modder rewrote the 2009 shooter, and chasm then added rebuilt Skate 3 mechanics on top. It is a bigger job, but you get one game running one process, with fewer bridge problems.

3. Decompiled characters dropped into a host

The third approach reuses work the community already did. Mario in Elden Ring, according to VGTimes, uses the long-running Super Mario 64 decompilation: a ready-made Mario that receives floor, wall and controller data from the host game. That is why it looks and moves like the real thing, and also why it needs your own legally obtained copy of Super Mario 64, not a downloaded ROM.

Where does AI come in?#

This is the contested part. The AI angle has driven most of the attention, and most of the backlash, so it is worth separating what is documented from what is hype.

What Universal Modder actually is

Universal Modder is an MIT-licensed, Python-based plugin for Claude Code. It does not make mods by magic. It gives the AI agent a workflow: identify the game's engine, examine and decompile code, find a mod loader, build the change, test it in the game, record it and package it. Per its description, it bundles playbooks for around a dozen engines, including Unity, Unreal, Source, Bethesda's engine, Godot and Minecraft. It has a dedicated "mashup-mods" workflow for ports, reimplementations and using a decompiled game as a code library. Its example mods are small and humble: new weapons and a boss in Terraria, a new civilization in Age of Empires II.

It also has stated limits. It is built for offline, single-player games that you own, it refuses to inject into online games with anti-cheat, and it will not help bypass DRM or ownership checks. Setup needs Python 3.10 or later and ffmpeg, and generating new art or audio needs a separate API key for an asset service. And it is not free to run in practice: it needs a paid Claude Code account, and a long modding session burns real usage.

Who used what

VGTimes lists the AI tools it found credited across the viral projects: Anthropic's Claude (the Opus line most often, and Claude Code as the interface), OpenAI's Codex, DeepSeek and others. It also reports how long some of them took: the Minecraft-in-GTA 5 project was built in about two days of agent sessions, and an Escape from Tarkov gear mashup for Skyrim in about eleven hours. By contrast, one Minecraft-inside-Super-Mario-64 project was hand-coded over two months with minimal AI.

Here is the important caveat. ResetEra users, and tech outlets, have pointed out that for many of the viral clips it is unclear whether AI was used at all. Passthrough techniques existed before agents, and some of the best-known pieces build on existing community work such as decompilations and recompilation tools. We checked the SkyCraft repository's documentation and it does not describe AI use; VGTimes says the project credits Claude, so that is a point to verify against the repository's commit history before anyone writes it down as fact.

The honest summary: AI agents make the boring but huge parts, like reading unfamiliar engine internals and writing glue code, dramatically faster. They do not design the experience.

The mashups, sorted by what you can actually play#

A lot of the confusion online comes from treating every clip as a release. Here is the state of play as of 6 October, based on repositories and reporting we could confirm. Check each project's page for the current status, because this is moving daily.

Take the "reported downloadable" rows with the usual care: they come from a third-party roundup, not from us installing them.

SkyCraft: the one you can try today#

Of everything on the list, SkyCraft is the most substantial, and its repository says more than the clips do. You play Skyrim with Minecraft's rules: Minecraft's movement (walking, sprinting, jumping, crouching, swimming), its inventory and HUD, block breaking and placing that persists in Skyrim's world, and combat against Skyrim NPCs with damage scaling. Your actions feed back into Skyrim's skill progression. It even supports Minecraft multiplayer for up to 100 players, although that applies to the Minecraft world only.

It is also upfront about being rough. The project describes itself as early and experimental and lists the problems: Skyrim's opening sequence can cause game-breaking issues, you cannot use Skyrim's inventory, magic or shouts while playing in Minecraft mode, Minecraft weapons cannot damage Skyrim objects, all interiors share one coordinate space, and camera mods conflict. The repository sat at around 1,000 stars and 67 forks when we looked.

Requirements are real: Skyrim Special Edition or Anniversary Edition on a recent runtime (tested on 1.7.104), SKSE64 and Address Library, roughly 3 GB of extra memory, and a Minecraft Java Edition licence tied to a Microsoft account. SkyCraft bundles the launcher, Fabric and Java for the Minecraft side.

Not everyone has been kind. Kotaku's Amelia Zollner tried it and described missing textures, invisible walls and mismatched materials, such as metal gates dropping wood. Players also received endgame Minecraft items with no progression. Her wider point was that the mashups do not synergise: stacking mechanics from two games is not the same as designing a new one.

Minecraft in Elden Ring: the clip that started it#

The mashup behind the 22-million-view number is Tobyn Jacobs' Minecraft in Elden Ring. The showcase puts Steve in the Lands Between with Minecraft's hotbar, hearts, hunger and armour bars on screen, about 1,600 items and working redstone: levers flip, pistons push, lamps light. The headline claim on X was that he had put the whole of Minecraft into Elden Ring, and that it runs on Mac.

It is, as of today, not downloadable. Jacobs said he was open to releasing it but had made it while messing around. Meanwhile VGTimes warns that fake "official" downloads have appeared on GitHub for it. Do not install anything claiming to be it.

Mario in Elden Ring, and the real-engineering counterexample#

Deltaroo's Mario mod went viral for a simple reason: it is funny to watch a plumber with perfect Super Mario 64 movement take on FromSoftware bosses. The guest character is the decompiled Mario receiving the host's collision data, which is why the jumps, long jumps and wall kicks feel right.

It also prompted the most interesting counter-example of the week. Games.gg reported on a modder called Funny-Bones who rebuilt Elden Ring's player movement and combat logic from scratch in Rust, as a portable controller system, and a second modder applied it to Skyrim, adding stamina management, dodge timing and committed attack animations. The article stressed that this was engineering rather than a prompt, and it had not been released when it ran. That is the fork in the road for this whole trend: AI-assisted glue and clip-ready demos on one side, careful, reusable systems on the other.

The limits nobody puts in the clip#

The viral videos are edited. The repositories are more honest. VGTimes reports a handful of consistent ceilings:

• Object caps. Guest games top out at around 1,500 spawned objects before the host game crashes. The Minecraft-in-GTA 5 project allows only about 400 placed blocks.
• PC only. Every mashup depends on two programs running side by side and reading each other's memory. None of this works on PS5, Xbox or Switch.
• Narrow compatibility. The pair has to be moddable: both games need community tooling, decompilations or open formats. The popular hosts, GTA 5, Skyrim and Elden Ring, all have big modding scenes.
• Fragility. A game update can break a mod overnight. Back up your saves.
• Performance. Two games means two sets of memory and CPU demands, which is why SkyCraft asks for roughly 3 GB of extra RAM before you add anything else.

Safety: what to avoid#

Treat this like any wave of viral mods, with extra suspicion, because attention attracts scammers.

1. Download only from the creator's own repository, and read the README before running anything. If a project says it has no release, any "official download" is fake.
2. Never take a modded game online. GTA Online bans modded clients, and Elden Ring's online features are not designed for this. Play offline.
3. Use your own copies. Mario in Elden Ring needs Super Mario 64 from a copy you own; downloading ROMs is piracy.
4. Be wary of malware. VGTimes recalls fake Minecraft mods spreading malware to a six-figure number of players earlier in 2026, and a trend like this is exactly the lure.
5. Back up saves before installing anything.

The legal question: publishers are watching#

Fan mods live in a grey area that depends on publisher goodwill, and bridging two companies' games makes it greyer, because there are now two sets of lawyers. Publishers have a long record here. Activision shut down the SM2 Modern Warfare 2 overhaul with a cease and desist in May 2023, and killed the H2M mod for Modern Warfare Remastered a day before its release in August 2024. VGTimes also reports that Rockstar updated its modding guidelines in September 2026 to bar other companies' content, and that Activision filed a complaint against a decompiled Modern Warfare 2 post on 2 October. Treat those two items as reported, not independently confirmed by us.

A passthrough mashup does have one structural advantage: it distributes only the bridge, not either game, and each player brings their own copies. That is also what Universal Modder's documentation says it does, sharing methodology rather than game files. But a legal edge is not a legal shield, and a project that bundles a decompilation or loads another studio's assets is the first thing a takedown targets.

What this could become (our speculation)#

Everything from here is opinion, so treat it as such. But some outcomes look likely enough to be worth discussing.

1. Mashups stop being stunts and become a mod category. Garry's Mod comparisons show up in the ResetEra thread for a reason: a novelty trick can seed a whole sandbox culture. If the tooling stabilises, expect "bring your own two games" launchers that handle the bridge for you, with compatibility lists per pair. The hard part is not the idea, it is making the engine hooks survive game updates.

2. The real prize is portable rule sets. The Rust controller from the Elden Ring combat project hints at the durable version of this idea: a combat or movement system written once and dropped into several hosts. Imagine a stamina-and-dodge system, a survival crafting layer or a platforming moveset that you install like a plugin. That is more interesting than watching one game sit inside another, and it needs good design, not just glue.

3. Studios may respond with official support or official bans. Some will quietly start supporting cross-game hooks, perhaps as sanctioned crossover events or a "mod bridge" in live-service titles, and others will lock down their anti-cheat and terms. The first big publisher to publish clear rules for this, rather than a patchwork of takedowns, will set the pattern.

4. Console is a wall, for now. Closed platforms do not let two games share memory, so mashups stay on PC unless a platform holder builds an official route. Cloud streaming could make a hosted "mashup server" technically possible, but that raises licensing questions nobody has answered.

5. AI will lower the floor and raise the noise. The same tools that let one modder prototype in two days will flood Nexus-style sites and social feeds with clips and low-effort releases. The critics are right that most of it will be forgettable. Quality will come from people who treat the agent as a fast intern and still design the experience.

6. Preservation and mashups will feed each other. Recompilation and decompilation projects, the kind that turn an old console game into a native PC build, are the raw material for decompiled characters and systems. If those projects keep growing, expect more classics to become "guests" in modern hosts.

7. Expect the backlash to shape the norms. Anti-AI sentiment among players is already strong, and some will reject anything labelled "vibe-coded". Creators who are open about what the AI did, and what they designed by hand, will do better. Modding has always run on reputation.

Our take#

Judged as games, most of today's mashups are tech demos: funny for five minutes, rough after that. That is exactly what Kotaku's review and the ResetEra thread say, and the evidence in the SkyCraft repository supports it. Judged as a signal, they are something else. A modder with a laptop and an AI agent can now stand up a bridge between two commercial games in a weekend, and the community's best tools, decompilations, recompilations and open formats, are lining up to make that easier.

If you want to try one, SkyCraft is the clearest place to start: open source, documented limits, and honest about being experimental. Keep it offline, back up your saves, and keep your expectations at "wild experiment" rather than "new game".

We will keep tracking releases, takedowns and the first mashup that is genuinely fun to play for more than ten minutes. If you build or find one, tell us.

Sources and further reading#

• SkyCraft on GitHub (Minecraft in Skyrim)
• Universal Modder on GitHub
• VGTimes: how the AI game mashups work
• Kotaku: Modders, please stop putting games inside other games with AI
• Tech4Gamers: AI is now allowing modders to merge entire games
• Games.gg: Skyrim mod adds real Elden Ring combat
• ResetEra: passthrough modding thread
• Forbes: "Minecraft in Elden Ring": vibe coders are remixing video games with AI

Related on Game Avant: Skyrim, Elden Ring, Minecraft: Java Edition, Super Mario 64, Grand Theft Auto V, Call of Duty: Modern Warfare 2 and Skate 3.