Obungo, Mul Daya Ancestor

At the beginning of combat on your turn,
up to one target land you control becomes
an X/X Elemental creature with trample
and haste until end of turn, where X is
Obungo's power. It's still a land.
Landfall - Whenever a land enters the
battlefield under your control, put a +1/+1
counter on target creature.