Fenris, the Rimebound

Menace
Fenris, the Rimebound enters tapped and doesn't untap during your untap step.
{3}, sacrifice a creature: Untap Fenris and put a +1/+1 counter on it. If {s} was spent to activate this ability, Fenris gets +1/+0 until end of turn.

The Warden of the shard of Aramis lies bound in the coldest reaches of his world, anger and resentment mantaining the frozen wastes alive and drifting through the Multiverse.