Zakhalt, Aerie Sovereign

Flying
Whenever a creature you control deals combat
damage to a player, add {g} or {w}. This mana
doesn't empty from your mana pool this turn as
steps and phases end.
Whenever you cast a creature spell, if you spent
mana only from Zakhalt, Aerie Sovereign to cast
it, it enters the battlefield with a flying counter
on it.