Walk in a goomba

From Glitches

From the game Yoshi's Island for the Super Nintendo

Go to a level with goombas in it. Now, jump on it so it gets squished flat. Ride it for a while and then run off the screen and run back and jump on the goomba. When you jump on it, it should still be flat. After a couple of tries of running away and then back, when you jump on the goomba, it should return to its normal size. While it does this, Yoshi will be standing inside of the goomba for a second or so. Then, Mario will be repelled off and you'll have to go catch him.

Submitted by: kornyhatemachine