The Gravemind

Trample, Infect

The Gravemind's toughness is equal to the number of Flood creatures you control

Each land you control is a 1/1 Flood creature in addition to its other types.

When a creature dies, if it wasn't Flood, create an
X/X Flood creature token where X was the creature's power, then put a +1/+1 counter on each flood you control.