Swarm Hydra

Symbiote (If a creature enters the battlefield with
equal power or equal toughness to this creature, put a
+1/+1 counter on both creatures.)
Creatures you control enter the battlefield with a number of +1/+1 counters equal to the number
of +1/+1 counters on Swarm Hydra.
{1}{u}{g}: Create a 0/0 Ooze token.