Mega Koopa

The Mega Koopa is a giant Koopa Troopa in Super Paper Mario that got a Mega Star.

Once an ordinary Koopa Troopa, he sees Mario coming and runs for his life. He hits a block containing the Mega Star and turns huge (using the same animations that any other character would when they used a Mega Star). Mario or Peach (Bowser and Luigi will also encounter it once they join later on) needs to get giant to defeat the Koopa, but he can be defeated by an explosion of Boomer, Bowser's firebreath,Luigi's Super Jump or one of the 4 heroes grabbing a Mega Star on the left side of the place. Oddly enough, when looked at in 3D, the Mega Koopa is 3D instead of flat, though all "Mega" characters may have this characteristic. This Koopa is not to be confused with a Gargantua Koopa Troopa.

Trivia
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 * This is perhaps the only occurrence of a regular enemy using a power-up item in a Mario game, though they were originally going to in another platformer, New Super Mario Bros.