Quirion Healer

Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield.
They remain paired for as long as you control both
of them.)
As long as Quirion Healer is paired with another creature, both creatures have undying. (When a creature with undying dies, if it had no +1/+1 counters
on it, return it to the battlefield under its owner's control
with a +1/+1 counter on it.)