Descrying One

At the beginning of your end step, choose flying,
first strike, double strike, haste, deathtouch,
hexproof, indestructible, lifelink, menace, reach,
trample, or vigilance. If a creature an opponent
controls has that ability, note that ability.
Otherwise, proliferate.
Creatures you control gain abilities noted with
Descrying One, and creatures your opponents
control lose abilities noted with Descrying One.