Pearl Diver

Submerge (You may have this creature enter the battlefield with a -1/-1 counter on it. If you do, it
becomes submerged and it can't be blocked.)
Whenever Pearl Diver deals combat damage to a player, you may flip a coin. If you win the flip,
create a number of colorless Treasure artifact
tokens with "{t}, Sacrifice this artifact: Add one
mana of any color." equal to Pearl Diver's power.
If you lose the flip, sacrifice Pearl Diver.