Relentlessness V2

Haste As an additional cost to cast this spell, you may sacrifice a creature. If you do, this spell’s mana cost is reduced by the sacrificed creature’s mana value. When this creature enters, if {B}{B}{B} was spent to cast it, until end of turn, you may play lands and cast spells from your graveyard. If a card would be put into your graveyard from anywhere this turn, exile it instead. When this creature enters, if {R}{R}{R} was spent to cast it, exile cards from the top of your library until you exile a nonland permanent card. You may cast it by paying life equal to its mana value. Put the exiled cards on the bottom in a random order. When this creature enters, if {G}{G}{G} was spent to cast it, destroy each nonland permanent with mana value 2 or less. Add one mana of any color for each permanent destroyed this way.