As requested by Roberto Zampari, here's a Whimp sprite that behaves just like NSMB2's whomp. When mario reaches near, it jumps and, when it reaches the ground, it slaps the ground with its face.
In order to kill it, while it's lying on the ground, you must spinjump in it, and it'll break.
Credits go to Squishy Rex for drawing the graphics that come included.
Now SA-1 hybrid.
(Rykon-V73): Converted the sprite into a .json file. My version uses palette 9, but it can be changed, by changing every $03 from PROP: db $03,$03,$03,$03 to $0D. And added a .gif. Blame my laptop for the .gif.