Mummipokey

Mummipokey is the second boss in World 2 of New Super Mario Bros. He is a mummified Pokey.

In this battle, Mummipokey pops out of the ground at different places throughout the battle. Mario or Luigi must Jump on its head three times to beat the boss and access World 3. It is also possible to just wait for it to pop up at a low height and hop on its head normally.

However, if Mario wants to access World 4, the plumber can defeat Mummipokey as Mini Mario. Mario must Ground Pound Mummipokey's head three times as Mini Mario to access World 4. When only one body segment appears, it cannot be jumped on as it will go back into the ground. If so, just wait until it comes out again.

Trivia

 * An issue of Nintendo Power also (incorrectly) stated Mummipokey to be a Sandworm.