Derpvee, Avatar Of Derp

Derpvee enters the battlefield with 3 derp
counters on it.
Creatures with derp counters on it have +2/+2
for each derp counter on it.
Whenever Derpvee attacks, you may put a derp counter on Derpvee.
Whenever Derpvee blocks a creature, you may
move a derp counter from Derpvee onto that creature, if you do, gain control of it.