Ouroboros, Serpent Eternal

Delve.
Ouroboros, Serpent Eternal can be cast from
your graveyard.
Ouroboros, Serpent Eternal enters the battlefield
with X +1/+1 counters.
If a creature card with flying was exiled with
Ouroboros, Serpent Eternal's delve ability,
Ouroboros, Serpent Eternal has flying. The same
is true for first strike, double strike, deathtouch,
haste, hexproof, indestructible, lifelink, reach,
trample, and vigilance.