Ellvanwin the Enigma

Deathtouch, Flying, Lifelink, Vigilance
Changeling
Green permanents you control have hexproof.
Spells and abilities your opponents control can't
cause you to reveal your hand or discard cards.
At the beginning of your upkeep, target opponent reveals their hand, you may choose a nonland
card from it and exile it. Until end of turn, you
may cast that card. At the beginning of your
end-step, return all cards exiled with Ellvanwin
to their owners hand.