Horus, The Lupercal

{r}{b}: Sacrifice a red creature: Deal 3 damage to any target, if the sacrificed creature was legendary, deal 6 damage instead
{g}{b}: Sacrifice a green creature: Add 2 to your mana pool, if the sacrificed creature was legendary, add 3 mana instead
{w}{b}: Sacrifice a white creature: gain 5 life , if the sacrificed creature was legendary, gain 10 life instead
{u}{b}: Sacrifice a blue creature: draw a card , if the sacrificed creature was legendary, draw a card and you my cast it without paying mana