Most people today mean when they say “Fire Red ROM hack.”
The hack introduces a range of creative squirrel-inspired Pokémon, each with its own unique type, stats, and moves. Some are obvious, like the "Squir" (a Fire-type squirrel with a flame on its tail), while others are more imaginative, like the "Nutrino" (a Electric/Fighting-type with a hamster-like appearance). fire red squirrel rom
As with any ROM hack, you cannot play this directly on hardware (without a flashcart) or download a pre-made game file legally. You need to patch the file yourself. Most people today mean when they say “Fire Red ROM hack