False Wario

From the Super Mario Wiki

The False Wario is the seventh boss in the NES version of the game Wario's Woods. He looks exactly like the "real McCoy", but is actually simply a convincing fake. He has the power to make one whole row of mixed enemies fall. After defeating the boss, Wario pretends to admit defeat, but quickly informs Toad that the Wario he defeated was a fake, and the real one is "ready to rumble!" Toad must then clear 30 more rounds and defeat De Buu and Shiisa again before fighting the "real" Wario.

False Warios also appeared in the game Wario Blast: Featuring Bomberman!. In this game, an army of False Warios aided their master Wario in his bid to loot Planet Bomber, the home of Bomberman. Bomberman had to fight hordes of False Warios before engaging the real Wario in one-on-one duels.

[edit] Game Appearances

Title	Description	Release Date	System/Format
Wario's Woods	Boss	1994	NES
Wario Blast: Featuring Bomberman!	Enemy	1994	Game Boy