Yog's Brain

Brain of Yog-Dzewa. Source of all evil ever to come out of the dungeon.

Ranged-Only Attacks: Can only attack enemies at range (uses zap/lightning attacks)
Paralysis Strike: Has 33% chance to stun the target on hit (from 3 to 1 damage roll)
Summoning: When damaged, summons Nightmares (scaled to 10x difficulty factor) and alerts all other mobs in the level to its position
Retreat Tendency: Tends to move away from enemies when in hunting state
Immunities: Immune to Paralysis, Amok, Sleep, Terror, and Burning
Resistances: Resistant to Lightning and Toxic Gas
Mechanical Nature: Cannot be turned into a pet

Appears as a secondary boss in the battle against Yog-Dzewa
At the start of the Yog battle, 2-3 other Yog organs (including Yog's Brain) are randomly spawned from the set: Rotting Fist, Burning Fist, Yog's Brain, Yog's Heart, Yog's Teeth
Cannot be turned into a pet

Focus on Yog's Brain as it has high damage output and can stun
Be aware of summoned Nightmares when taking damage
The paralysis effect can be dangerous in boss fights, so be prepared with healing items
Attacks from range as it can only perform ranged attacks
Staying mobile can help avoid the summoned creatures