Pyschosis

Psychosis is an insane mode Chaotic boss. It must be defeated before Cranius can be summoned. It can be summoned by removing all Corruption from a world, (excluding underground corruption) in which case it spawns instantly afterwards, or using a Mind-Bending Brain in the Purity at night.

The boss itself is a slightly larger, corruption-themed version of the Brain of Cthulu. Upon spawning, Psychosis is accompanied by twelve True Creepers, which orbit the boss at high speed, following it wherever the boss teleports to. Creepers do not respawn once they are killed. All Creepers must be destroyed first before Psychosis enters its second phase, where it then becomes vulnerable to attack. It is also accompanied by two Psychosis Hands, which are the same as Skeletron's hands except much more powerful.

First phase
In this phase Psychosis hovers directly above the player, moving as fast as needed to stay directly above. It fires down Cursed Shadow projectiles at the player from its eye while its hands attack the player.

Second phase
In this phase Psychosis will charge directly at the player, attempting to do melee damage, while firing Phantasmal Deathrays at the player in short durations. After five seconds, it backs away and begins to summon Mindless Spheres (homing balls of purple energy) in bursts of ten to twenty, which disappear after around six ten seconds. If both Psychosis Hands are destroyed, Psychosis begins to orbit the player in small circles, firing Phantasmal Deathrays in longer durations and discarding its other attacks.

Expert Mode
In Expert Mode, Psychosis's attacks do 25% more damage, and he adds a new attack. Around every ten to thirty seconds spikes of purple stone rise out of the ground, inflicting the Stoned debuff on contact.

Drops
Pyschosis Mask (14.29)

Pyschosis Trophy (10%)

Super Healing Potion 5-15

Souls of Dread 10-30

Pyschosis Finger (1/5)

Creepy Staff (1/5)

Ocular Orbiter (1/5)

Deathweed Pike (1/5)

Greymatter (1/5)

Pyschosis Loot Bag (100%, expert mode only)

Brain Rain (100%, inside loot bag)

Achievement
Braniac "Defeat Pyschosis, the hidden lord of the Corruption's shadows."

Defeat Psychosis for the first time.

History

 * 1.4.8: Cursed Shadow attack was added.
 * 1.4: Introduced.