Myr Battlesphere

Set: Commander 2013 (#247)

Rarity: Rare

Type: Artifact Creature — Myr Construct

Mana Cost: {7}

P/T: 4/7

When this creature enters, create four 1/1 colorless Myr artifact creature tokens. Whenever this creature attacks, you may tap X untapped Myr you control. If you do, this creature gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.