Sidith, Harbinger of Fear

Fear
Whenever Sidith, Harbinger of Fear deals combat damage to a player, until end of turn creatures that player controls get -1/-1 for each +1/+1 counter on Sidith, Harbinger of Fear.
{b}{b}{b}{t}: Destroy target mono colored creature, place a +1/+1 counter on Sidith, Harbinger of Fear.