Quadracrab

This creature enters the battlefield with X +1/+1 counters on it.
{u},{t}: Draw a card. Put a +1/+1 counter on Quadracrab.
{u}{u}, Discard 3 cards: Create a copy of
Quadracrab that has no counters on it. Move half
of the +1/+1 counters on Quadracrab to the copy.
Then if you control 4 creatures named
Quadracrab on the battlefield, destroy all
non-crab creatures.