Not every game-in-game crossover is an AI project. Modders have been putting one game’s characters, movement or rules into another for decades with model swaps, script extenders and hand-written code. The 2026 mashup wave brought a lot of attention to that older craft as well, and clips of conventional mods often circulate alongside the AI-built ones.
This site lists them so the record is complete, and marks them conventional mod so it’s clear an AI agent wasn’t part of the credit. If a creator later says they used one, the entry changes.