From Pathfinder Book of the Dead, which isn't enabled.

Festering Gnasher

CREATURE 1

A festering gnasher is a floating head covered in infectious pustules and hollowed out by decay.

Beheaded are disembodied floating heads transformed into undead. They are natural candidates for a necromancer's "project minion," due to the inexpensive cost of creation and endlessly customizable nature. In any lair occupied for long by practicing necromancers, it isn't uncommon to find a handful of floating heads roaming about, each exhibiting completely different characteristics and even degrees of expertise in their creation.

Perception +8; darkvision

Skills Acrobatics +7 (+9 to Maneuver in Flight)

Str +3, Dex +4, Con +1, Int -3, Wis +3, Cha +0

AC 16; Fort +4, Ref +9, Will +6

HP 18, void healing; Immunities bleed, death effects, disease, paralyzed, poison, unconscious; Weaknesses vitality 2

Void Healing

A creature with void healing draws health from void energy rather than vitality energy. It is damaged by vitality damage and is not healed by vitality healing effects. It does not take void damage, and it is healed by void effects that heal undead.

Speed 15 feet, fly 25 feet

Melee Jaws +9 (agile, finesse, reach 0, unarmed), Damage 1d4+3 piercing plus Brain Rot

Brain Rot (disease)

Saving Throw DC 14 Fortitude

Onset 1 day

Stage 1 Stupefied 1 (3 days)

Stage 2 Stupefied 2 and Slowed 1 (1 day)

Stage 3 Paralyzed with spasms (1 day)

Stage 4 death

Pathfinder Book of the DeadOGL