Gemini Portrait
Character Information
Character Type Boss
Floors of


Base Health
Heart flash
140 and 140
Items Dropped Boss Pool

Gemini is an enemy in The Binding of Isaac that is present both as a Boss on both The Basement and The Catacombs (Double Trouble) floors and as a Monster during Boss Rush, in Boss Challenge Rooms, and on later floors. The larger being is named Contusion, it having a contusion in its head, and the smaller, parasitic being, is named Suture, it having stitches in its head.


Contusion attacks in a set pattern:

  1. Contusion will walk towards Isaac, dealing contact damage.
  2. Contusion will sprint towards Isaac, dealing contact damage.
  3. Contusion will stop to breathe, then repeat the pattern, still dealing contact damage.

Suture has two different stages.

  1. While Contusion is still alive, Suture will slowly move towards the player while guided by Contusion. If the player is in Suture's line of fire, it will shoot a single tear at the player. Suture can still deal contact damage in this stage.
  2. While Contusion is dead, Suture will turn red and quickly move towards the player. The player can knock back Suture easily, making it more difficult to avoid.

Champion Variants

Contusion has a chance to spawn (with Suture) as one of two champion variants:

  1. Gemini will be green and separated from Suture.
  2. Gemini will both be blue and have more health.


  • Gemini was originally supposed to be a boss in Gish, another one of Edmund McMillen's games.
  • Gemini is a constellation associated with Zodiac symbol Twins.