Agrek, the Growth Mage

Cannot be countered
Agrek enters the battlefield with X power and toughness for X is how much you cast him.
When Agrek enters the battlefield, all players sacrifice all artifacts and enchantments. All creatures you control get +1/+1 for each artifact and enchantment that was sacrificed. Whenever a creature deals combat damage to a player, that creature gets +1/+1.