Antenora, Worm of Autumn

Whenever an opponent's commander attacks you and is unblocked, put a +1/+1 counter on Antenora, Worm of Autumn.
Whenever Antenora, Worm of Autumn deals damage to you or a creature you control, put two +1/+1 counters on Antenora.
As long as Antenora, Worm of Autumn has seven or more +1/+1 counters on it, it gets +7/+7 and has hexproof, menace and trample.