Sword of Self Undone

When Sword of Self Undone is equipped to a creature, place five heartbeat counters on that creature. Equipped creature gets +1/+1 for each heartbeat counter on it.
Whenever equipped creature attacks, remove a heartbeat counter from that creature. Then,
if there are no heartbeat counters on equipped creature, sacrifice it and you gain 5 life.
Equip {b}{r}