Impostor Bowser

The False Bowsers first appeared in Super Mario Bros. Mario had to fight seven of them (one in each castle) before he could reach Bowser's Castle and fight the real thing. Hitting the fake Bowser with fireballs would show that they were really just common enemies with a spell cast on them. False Bowsers returned in Super Mario Bros.: The Lost Levels, aiding the true Bowser in his second bid for the Mushroom Kingdom throne. In this game, multiple False Bowsers would occasionally appear in one castle.

A similar enemy, known as the Bowser Clone, appeared in Super Mario RPG: Legend of the Seven Stars.