Bor'Akdos, the Flame Pact

As long as each opponent has six or less creatures, Bor'Akdos isn't a creature.
Adamantine, double strike, havoc, sunforge 3
Whenever a creature you control attacks, it gets a +1/+1 counter. Whenever a creature you control deals combat damage to an opponent, put a -1/-1 counter on target creature he or she controls.
{c}{r}{w}{b}, {t}: Artifacts you control have adamantine until your next turn.