Blood-Slime Elemental

Trample
Devour X (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters
the battlefield with X +1/+1 counters for each of those creatures.)
When Blood-Slime Elemental kills a creature in combat, exile that creature. Put X +1/+1
counters on Blood-Slime Elemental, where X is
equal to the exiled creature's toughness.