Xathrid Necromancer

Create two 1/1 colorless Sliver creature tokens.

T: Put a charge counter on this artifact. T, Sacrifice this artifact: Destroy each nonland permanent with mana value equal to the number of charge counters on this artifact.

Islandwalk (This creature can't be blocked as long as defending player controls an Island.) Whenever this creature attacks, you may exile target creature defending player controls until this creature leaves the battlefield. (That creature returns under its owner's control.)

Sliver creatures you control get +3/+3.

T: Each creature attacks this turn if able.