Derrak, Caller of Night

Flying, lifelink, haste
Derrak, Caller of Night enters the battlefield with a +1/+1 counter.
Derrak attacks each turn if able.
Put a +1/+1 counter on Derrak: Prevent all damage Derrak would deal this turn. Activate this ability only once each turn and only as a sorcery.
Remove a +1/+1 counter from Derrak: Until end of turn, whenever Derrak deals damage to a player, that player discards a card or loses 3 life.