[zero_iq]

You might be thinking of SheepShaver, a Mac emulator for BeOS and Linux. Its name is a play on the name ShapeShifter, an earlier emulator by the same develope, which was an Apple II emulator for the Amiga.

[lostgame]

Nope, the utility was actually called ShapeShifter: (I used to make themes for it)

https://www.macintoshrepository.org/11531-shapeshifter-osx-t...