Gallium Goo

A large ooze of a milky white complexion, a gallium goo takes its name from the fluid metal known to corrode other metals through direct contact. Incredibly caustic to all but the most powerful magical metal objects, gallium goo gain sustenance by bonding their bodies with metal they encounter, making it brittle and unusable. Curiously, this process seems to injure the ooze, and more than one gallium goo has been defeated by allowing it to eat itself to death. This unusual behavior flies in the face of all evolutionary theory, giving credence to the idea that these creatures are in fact artificial beings created by an unknown intelligence. Nevertheless, gallium goo have thrived in the wild, and will overpower any living creatures that get between them and a tasty metallic morsel.


Large ooze, unaligned

Armor Class 19 (natural armor)
Hit Points 161 (17d10 + 68)
Speed 30 ft., climb 30 ft.

21 (+5) 15 (+2) 19 (+4) 1 (-5) 6 (-2) 1 (-5)

Saving Throws Dex +6, Con +8, Wis +2
Skills Perception +6
Damage Resistances bludgeoning, piercing, and slashing from metal weapons
Damage Immunities poison, psychic
Condition Immunities blinded, charmed, deafened, exhaustion, frightened, prone
Senses metalsense 120 ft. (see traits), blind beyond that radius, passive Perception 16
Challenge 10 (5,900 XP)


Amorphous. The goo can move through a space as narrow as half an inch wide without squeezing.

Diffusing Touch. When the goo touches a metal object or one that contains a significant quantity of metal, it can choose to lose 15 hit points to break the object, making it brittle and unusable. Affected magical objects instead lose half their maximum hit points.

Metalsense. The goo can perceive any metal within 120 ft. through its sense of smell.

Spell Resistance. The goo has resistance to damage from spells and magical effects.


Multiattack. The goo makes two pseudopod attacks.

Pseudopod. Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit: 11 (1d10+5) bludgeoning damage. If the target is a creature, the goo may grapple it (escape DC 17).

Regenerate. The goo regains 26 (4d10+4) hit points.

Slingshot. Ranged Weapon Attack: +9 to hit, range 60 ft., one target. Hit: 23 (4d8 + 5) bludgeoning damage. When the goo makes this attack, it launches its entire body at the target, landing in the nearest unoccupied space to the target.

Ref: TPKB1 p176