The Knave, Dire Balemoon

Lifelink, Deathtouch, Vigilance
Whenever The Knave, Dire Balemoon attacks you
may pay X life. If X is 5 or more The Knave, Dire Balemoon gains two +1/+1 counters. If X is 10 or
more The Knave, Dire Balemoon gains Double
Strike until end of turn.
Whenever you gain or lose 5 or more life at once,
draw a card.
At the beginning of the end step, if you did not lose
or gain 10 or more life this turn transform The
Knave, Dire Balemoon.