Kiss-Shot Heart-Under-Blade

Kiss-Shot Heart-Under-Blade enters the
battlefield with four +1/+1 counters on it.
If Kiss-Shot Heart-Under-Blade would die,
instead remove a +1/+1 counter from it and
create a Limb token.
Whenever you gain life as a result of sacrificing a permanent, put a +1/+1 counter on Kiss-Shot
Heart-Under-Blade.