Slimy, undead friend.

indestructible
Whenever Slimy, undead friend attacks or blocks,
you may put a +1 +1 counter on it.
{1}{g}{g},{t} remove a +1 +1 counter from Slimy,
undead friend : Destroy target artifact.
{1}{b}{b},{t} remove a +1 +1 counter from Slimy,
undead friend : Destroy target creature.