Huntmaster Liger

King Caesar, Ancient Guardian (Huntmaster Liger)

Creature - Cat | Power/Toughness: 3 / 4 (CMC 4)
Mutate (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, other creatures you control get +X/+X until end of turn, where X is the number of times this creature has mutated.