Leviathan (German) [Renaissance] Commander 2011 Boast — Sacrifice another creature

Boast — Sacrifice another creature or artifact: Broadside Bombardiers deals damage equal to 2 plus the sacrificed permanent's mana value to any target

"Sometimes it is better to be swift of foot than strong of swordarm

Set: Commander Masters Type: Creature — Sliver Rarity: Rare Cost: {2}{B} Sliver creatures you control have lifelink

If you appease them

Set: Eventide Type: Artifact — Equipment Rarity: Rare Cost: {2} Whenever you cast a spell

Leviathan (German) [Renaissance] Commander 2011 Boast — Sacrifice another creatureSet: Renaissance Type: Creature Leviathan Rarity: Uncommon Cost: {5}{U}{U}{U}{U} Trample Leviathan enters the battlefield tapped and doesn't untap during your untap step. At the beginning of your upkeep, you may sacrifice two Islands. If you do, untap Leviathan. Leviathan can't attack unless you sacrifice two Islands. (This cost is paid as attackers are declared.)