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Template Grafts | Universal Monster Rules

Ferrofluid Ooze

Source Alien Archive 3 pg. 34
Ferromagnetic fluid, or ferrofluid, has long been a staple of spacefaring technology. Societies across the galaxy originally created this utilitarian substance by suspending coated nanometer-sized particles of magnetite in viscous liquid. As necessity demanded invention, later iterations of the magnetic liquid began to take on an almost lifelike temperament. The substance increasingly exhibited erratic behavior as engineers tinkered with heavily magnetized liquids, using experimental bioengineered substances to suspend magnetic particles. The final result of these developments was an emergent, though limited, sentience within certain pools of ferrofluid—a consciousness solely consumed with the search for ever-stronger magnetic fields.

Ferrofluid oozes can form virtually anywhere, but they are drawn to urban areas filled with magnets and ferrous metals and find solace in any place that thrums with electromagnetism. Their dark, aqueous bodies skulk low to the ground, and they often hide away beside magnetic machines in industrial districts or aboard starships and space stations. A few lucky oozes find caverns of naturally magnetized ore. Wherever the oozes travel, their magnetic properties reduce the vibrations of their movement, making them difficult to detect until their magnetic fields and unmistakable magnetic pull betray their presence. Ferrofluid oozes are usually about 3 feet in diameter.

While not inherently ill meaning, ferrofluid oozes often are at odds with the owners of the magnetic objects they covet. Usually utterly indifferent to organic life, ferrofluid oozes seek only to collect magnetic material— though they do defend themselves, and can attack when stubborn life-forms refuse to relinquish their magnetic goods. Ferrofluid oozes that collect a large amount of debris are even on occasion mistaken for scavenger slimes.

As ferrofluid oozes skulk around places profuse with magnetized materials, they occasionally leave behind droplets of magnetic fluid. So long as these droplets remain in the magnetized environments provided by their parent, their size and magnetic power grow in parallel with their access to additional magnetized material. Due to this propagation, it is not unusual to see several ferrofluid oozes enjoying the same magnetically charged environment, so experienced adventurers are wary when they find only a single ooze in such a place. Given enough time and magnetic material, multiple oozes can form into a single, much larger ferrofluid magneto-cluster around 8 feet in diameter.

Aliens in the "Ferrofluid Ooze" Family

Ferrofluid Magneto-Cluster12
Ferrofluid Ooze2

Ferrofluid Ooze, Ferrofluid Magneto-Cluster

Source Alien Archive 3 pg. 34

Ferrofluid Magneto-Cluster CR 12

XP 19,200
N Large ooze
Init +4; Senses blindsight (magnetism) 60 ft., sightless; Perception +22
Aura magnetic field (60 ft., Strength DC 16)


HP 200
EAC 26; KAC 28
Fort +16; Ref +12; Will +9
DR 10/piercing or slashing; Immunities ooze immunities; Resistances electricity 10
Weaknesses demagnetization


Speed 20 ft., climb 20 ft. (magnetic surfaces only)
Melee pseudopod +25 (6d4+20 B)
Space 10 ft.; Reach 10 ft.
Offensive Abilities magnetic leap (attach or engulf [6d4 + 20 B]), polarity shift


STR +8; DEX +4; CON +5; INT —; WIS +0; CHA +0
Skills Stealth +27
Other Abilities mindless


Environment urban
Organization solitary

Special Abilities

Demagnetization (Ex) If a ferrofluid ooze takes fire damage, any creature to which the ooze is attached is released. In addition, until the end of the ooze’s next turn, its magnetic field aura has no effect, and it can’t use magnetic leap.

Magnetic Field (Ex) A ferrofluid ooze is surrounded by a constant magnetic field that interferes with nearby technological equipment. Each time a creature within the field attacks with a technological weapon, it must succeed at a Strength check (DC = 10 + 1/2 the ooze’s CR) or take a –2 penalty to its attack.

Magnetic Leap (Ex) As a move action every 1d4 rounds, a ferrofluid ooze can move adjacent to a creature within its magnetic field that is either a technological construct or wearing or wielding technological equipment. This movement does not provoke attacks of opportunity. The ooze then automatically attaches to that creature, as per the attach universal creature rule. If the target creature is at least one size smaller, the ooze automatically engulfs the target (as per the engulf universal creature rule) instead of attaching to it.

Polarity Shift (Ex) Once per day as a full action, a ferrofluid magneto-cluster can shift the polarity of its magnetic field, causing it to briefly repulse magnetic objects. Each creature must attempt a DC 19 Reflex save for each technological item it is holding to avoid dropping it in an adjacent square. In addition, each creature that is a technological construct or wearing technological armor must succeed at a DC 19 Fortitude save or be knocked prone.