From Binding of Isaac: Rebirth Wiki
The Monkey Paw is a trinket.
- If Isaac has half a heart or less after taking damage, this trinket drops a Black Heart.
- The effect can trigger up to three times, after which the trinket will disappear.
- The fingers stuck out by the paw will change to display the number of triggers left.
- The effect can trigger more than once in the same room.
- The Lost will still die when carrying the trinket, with a Black Heart spawning afterwards.
- Has no extra effect while holding Mom's Box.
- This item is a reference to the supernatural short story The Monkey's Paw by W.W Jacobs.