Calmadae, the Great Sledge

Eternal (If Calmadae would be destroyed or exiled, return it to the battlefield under its owners control at the beginning of the next upkeep.)

As long as the equipped permanent is a planeswalker, it's a 4/4 Avatar creature in addition to its other types. Its loyalty abilities can still be activated.

Equipped creature gains +6/+1, firststrike, and trample.

{3}: Equip to target creature or planeswalker you control.