The Evil Mega Goomba is the King Goomba in Forest Island and the boss of World 6 in Super Princess Peach Wii. He had received Evil Mushrooms to give to the enemies to make Peach's journey harder. Peach, Perry, Patty, and Stafy entered his lair, hoping to find a way to stop the chaos but before they look around, he attacked.
He attacks by jumping in the air and pounding you, becoming invisible, and summoning Evil Goombas. To defeat him, you must run through his lair to find a stack of Mushrooms. Take one and throw it at him. Then you must use a Good Blast. Do this three times to defeat him and win a Good Star, which reverses the affects of an Evil Mushroom.