| Floors of
| Base Health||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:
- Contusion will walk towards Isaac, dealing contact damage.
- Contusion will sprint towards Isaac, dealing contact damage.
- Contusion will stop to breathe, then repeat the pattern, still dealing contact damage.
Suture has two different stages.
- 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.
- 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.
Contusion has a chance to spawn (with Suture) as one of two champion variants:
- Gemini will be green and separated from Suture.
- 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.