Slimebrew Extractor

When Slimebrew Extractor enters the
battlefield, put a -1/-1 counter on target
creature.
Whenever a creature with a -1/-1 counter
on it dies, you gain 1 life.
"The rat must be added alive. It is therefore
recommended to take it from the tail."
—Asmoranomardicadaistinaculdacar,
The Underworld Cookbook