Redwing, Hunted Glory

Haste, flying, prismatic (Whenever you cast a multicolored spell, put a +1/+1 counter on this creature.)
Manaburst (Whenever this creature deals
combat damage to a player, you may sacrifice a land. If you do, add three mana of any color.
Until end of turn, this mana doesn't empty from your mana pool as steps and phases end.)