A black bat with large fangs.


Killing 13 monsters heals Isaac for a half-heart, indicated by a special sound effect and a small "health up" graphic.

Any boss will count as one kill. Splitting apart Envy/Super Envy, Fistula, and The Fallen will count as one kill. Killing Flies does not increase the counter.

If the kill counter reaches 13 while at full hearts, the counter resets and the heal is wasted.


  • This item is useless to ???, since he cannot gain red hearts.
  • Breaking down Globins into their goo-form will count as a kill. Therefore, letting them regenerate and breaking them down again can allow the player to restore health easily.
    • Likewise, a room with multiple explosive enemies such as Gurgles can be used to restore health by killing all enemies but one, and letting them bomb open a door or an entrance to a Secret Room. Exiting the room with one enemy left will revive all enemies upon re-entry, who can be killed again.


  • XRay Vision - Allows the player to recover their hearts slowly yet indefinitely by repeatedly killing enemies in an uncleared room next to a Secret Room.
  • IPECAC - The high damage of poison bomb tears makes healing a necessity, as well as being able to easily force doors open to exit an unfinished room and make monsters respawn for more kills.
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