Er, Cipher-Wyrm

Vacant (Creatures with vacant are not affected by summoning sickness and enter with a -1/-1 counter for each colored mana spent to cast them.)

Flying

Whenever Er, Cipher-Wyrm attacks it gains Annihilator X where X is the number of creatures you control with even numbered power.

Er despises the shifting and irregular earth, it relentlessly scours the world of 'imperfections'.