The Gemini

The Gemini are two interconnected bosses like the Twins, only they are Brain of Cthulhu counterparts instead of Eye of Cthulhu ones. They consits of Amygdalazer and Spasmebellum, which are based on Retinazer and Spasmatism respectively. They are connected by their brain cord. One brain (Amygdalazer) is deep red, and one brain (Spasmebellum) is sky blue. Along with attacks taken from both bosses, they also use moves that involve both of them teaming up. They are War Mode bosses, and are summoned by using the Twin Lobes at night.

Phase 1
Amygdalazer and Spasmebellum fly around, invincible. They can melee you for 150 damage each and fly EXTREMELY fast, as well as teleport individually (the tether moves accordingly). There are two types of enemies inspired by the Twins, Retinas and Spasms. These enemies look like their conterparts' second phases, only smaller and less mechanical (like Wandering Eye-sized versions of the Optic Staff summons) and take the place of Creepers in the Brain of Cthulhu. Retinas fire lasers that deal 180 damage and give you the Weak debuff, and Spasms rapidly spew out Demonic Flames that deal 80 damage and always giving you the Demonic Inferno debuff. They can both melee you for 120 damage. While you must kill all the Retinas to attack Amygdalazer and all the Spasms to attack Spasmebellum, both types surround both brains. In addition to all this, they sometimes rapidly spin around each other, which spawns more Retinas and Spasms and does 200 damage.

Amygdalazer
After defeating all the Retinas, the top part of Amygdalazer's lobes split open, revealing a mechanical laser inside of it. It shoots a single, constant laser into the air, which comes back down at you. This laser deals 45 damage to you per second if you are standing in it, and slows you down immensely when trying to get out. It still spins with Spasmebellum, though it does not spawn any Retinas.

Spasmebellum
After defeating all the Spasms, the top part of Spasmebellum's lobes split open, revealing a blue glowing core inside of it. This core rapidly fires blue homing flares at you, which always inflict the Demonic Inferno debuff. Each flare does 50 damage as well. After 50 hits of damage from any source, the blue flares will die out. It still spins with Amygdalazer, though it does not spawn any Spasms.

After the Death of One Brain
When one of the two brains dies, it does not separate from the other brain. Instead, it is used in an attack that replaces its spin attack where it swings the dead brain around like a ball and chain. This does 195 damage in the first form and 210 damage in the second.

Drops

 * 20-40 Spirits of Blight (100%)
 * 10-30 Greater Healing Potions (100%)
 * 1 Gemini Mask (14.29%)
 * 1 Gemini Trophy (10%)

Amygdalazer (1 treasure only)

 * Orbital Laser (33.3%)
 * Cerebral Staff (33.3%)
 * Laser Needle (33.3%)

Spasmebellum

 * Demon Thrower (33.3%)
 * Twin Brains (33.3%)
 * Cosmic Storm (33.3%)