The Ground Pound Cancel Jump is an advanced trick used in Super Mario Maker. This trick allows Mario destroy a block or enemy with a Ground Pound and jump off it at the same time.
When an object is destroyed from a Ground Pound it will not completely disappear for 2 frames. By canceling the Ground Pound after destroying the object, it is possible to perform a jump or enter a door.
Variations
Brick Block
Door Entry
Jump
Chain Chomp Post
This version is much easier because Chain Chomp posts aren't immediately destroyed.