Sneak Attack II

: You may put a creature card from your hand onto the battlefield. That creature gains haste. Sacrifice the creature at the beginning of the next end step.

Sacrifice a creature: Add one mana of any color.

Play with your hand revealed. If you would draw a card, reveal the top card of your library instead. If it's a creature card, put it into your graveyard. Otherwise, draw a card. Whenever a creature is put into your graveyard from the battlefield, return it to your hand.

Whenever a creature enters, that creature's controller may have it deal damage equal to its power to any target of their choice.

Trample When this creature enters, sacrifice it unless you sacrifice any number of creatures with total power 12 or greater.