Derp

Flying, First strike, Haste
Derp enters the battlefield with X +1/+1 counters
on it, where X is the number of Creatures in your opponent's graveyard.
When derp enters the battlefield, destroy all creatures your opponents
control with power 2 or less.
Annihilator 5. Whenever a creature dies,
put a +1/+1 counter on derp.