Groundshaker

Groundshaker is a boss from Kingdom Hearts II.

Groundshaker is a titanic doppleganger-like Living Bone who roams the Pride Lands after Simba triumphs over Scar's Ghosts. The ghosts all merge to form the gigantic Heartless that is easily one of the biggest Heartless Sora ever fights, comparable only to the World of Chaos. The top of the beast is very much like a lush Savannah. He is the boss of the Pride Lands on the return visit.

Atop the beast is an unnamed witch doctor Heartless who resembles a Shaman. Similar to the Shaman, the witch doctor forms a relationship with Groundshaker. When the witch doctor's double-mask rotates, Groundshaker's head would also rotate. One side uses volcanic fire attacks, while the other side uses eerie electric magic.

It is unknown whether the beast or the witch doctor is the Heartless named Groundshaker. Timon hints that the witch controls the beast. It is entirely possible that they are one in the same, as the witch doctor sometimes merges with the beast. However, it is easy to tell what earlier Heartless inspired Groundshaker--he has uncanny resemblance in attack style to Behemoth from Kingdom Hearts.

Journal Entry
''A giant Heartless that appeared in the Pride Lands. He was created by the many illusions of Scar.''

The main body on the back of the creature controlled his bones, creating chaos in the savannah.

Trivia

 * It is believed that Groundshaker is the largest Heartless that Sora ever fought (excluding World of Chaos).
 * Based on the beta screen shots, many fans believed that Behemoth would appear in Kingdom Hearts II. Instead, the end result was Groundshaker.