Grendhelt, One with Decay

Wither
Whenever you experiment, place a -1/-1
counter on target creature.
Grendhelt gains +1/+1 for each creature with a
-1/-1 counter on it.
{2}{b}, {t}, discard a card: place a -1/-1 counter
on target creature, then proliferate.

"We are many. We are the forgotten, the fleshless, the
ones you despise. We are Grendhelt."