Amorphous Blood Beast

When Amorphous Blood Beast comes into play you may pay any number of life. Put a +1/+1 counter on Amorphous Blood Beast per life spent in this way.
Whenever Amorphous Blood Beast damages a player or creature put a +1/+1 counter on it per target damaged.
{t} sacrifice Amorphous Blood Beast to gain 1 life per +1/+1 counter.