Animosity

Whenever Animosity becomes blocked by a
creature, put a +1/+1 counter on Animosity.
Counters remain on Animosity as it moves to any
zone other than a player's hand or library.
{b}, Pay 1 life: Target creature defending player controls untaps and blocks Animosity if able.
Activate this ability only during the declare
attackers step and only if Animosity is
attacking alone.