Avex, Dimension's Wrath

Flying, haste
Whenever Avex enters or leaves the battlefield,
exile the top three cards of your library. Then,
put any number of those cards into your hand.
For each card you leave in exile this way, Avex
deals 3 damage to each opponent, and each
creature and planeswalker they control.
If this card leaves the battlefield, or is put into
your graveyard or exile from anywhere, exile
it with a binding counter on it instead.