Gemini

Gemini is a boss that can appear in. Each twin has 140 HP. The large twin is called Contusion and the small twin is called Suture.
 * Additionally in the.

Behavior
Gemeni starts as a pair of bosses connected together by an umbilical cord.
 * Contusion chases Isaac and periodically charges increasing his speed, but stops to catch his breath afterwards.
 * Suture, while attached to Contusion, shoots a projectile towards Isaac if not behind an obstacle.
 * If Contusion is killed, Suture detaches and begins charging furiously at Isaac. He has high momentum and takes extra knock-back from tears which can cause him to gain speed.
 * If Suture is killed, there is no change to Contusion's behavior.

Champion Versions

 * Cyan: No difference in behavior. However, Contusion will drop a Soul Heart if killed last.
 * Green: They start separated from each other and have no difference in behavior.

Arena
When fighting Gemini, the following obstacles can spawn:
 * Rocks in 4 different combinations
 * Rocks will always appear when fighting Gemini.

Trivia

 * Gemini appeared in the original The Binding of Isaac.
 * Gemini seems to be an example of a parasitic twin, with Suture being the underdeveloped twin, dependent on Contusion.
 * Blighted Ovum is the posthumous version of them, and Steven is the alternate version.
 * The Gemini pair is named after the astrological sign of the same name; the symbol of Gemini is a pair of twins.
 * The Gemini pair was originally designed to be a boss in Gish and was called Suture Contusion, with the larger twin being Contusion for the boot-shaped dent in his head.
 * Contusion is the medical name for a bruise, whereas suture is the medical name for a thread used to close gaping wounds, commonly called stitches.
 * The names of the brothers are inspired by a song by The Mars Volta
 * The specific lyric comes from "Cicatriz ESP."
 * In the Bestiary, Suture is referred to as "Gemini Baby".