Cerebral Parasite

These microscopic psionic parasites drift on air currents. Clear and almost transparent, they are invisible to the naked eye. When one floats near a psionic creature, it fastens onto that being's aura and begins slowly feeding on its psionic strength. They have two psychometabolic devotions, ectoplasmic form and immovability, and one telepathic science, probability travel.

Its feeding is so quiet that a host can go a long time unaware. Any psionic creature passing within 1 foot of a parasite draws it in, and it attaches to the aura, usually without the host realizing anything. Among psionic powers, only psionic sense, life detection, and aura sight reveal them, though spells that reveal hidden or invisible things also work. The host may suspect a problem when using powers.

For each parasite in the aura, every psionic power the host uses costs 1 extra PSP. The power still works, but the parasite soaks up the surplus. Once a parasite has absorbed 6 PSPs, it divides in two, and both then feed, so the infestation grows. Eventually the host cannot pay the total cost of a power, and it simply fails.

There are only two cures. A cure disease spell removes them, or the host can stop spending PSPs entirely until hunger drives them away. Each day of abstinence gives each parasite a cumulative 1% chance (to a maximum of 95%) of letting go. Since every parasite rolls separately, a badly infested host may need three or four months without psionics to be rid of all of them.

Also called psionic parasites, they have existed as long as psionicists have. Sages say an ancient order of wizards bred them to purge the planes of 'false mages,' meaning psionicists. Wizards still love that story, though no one knows if it is true. Their ability to travel to the Ethereal and Astral planes does lend it weight: they shift into the Ethereal innately and reach the Astral by probability travel.

At 15-year intervals a plague of these parasites sweeps the Prime Material Plane. During that time they become common and appear in groups of 4d8. Psionicists dread it and call it 'the year of weakness.'

Captured parasites make a superb weapon against psionicists, except that even the tightest jar cannot hold them forever. Each has a cumulative 1% chance per day of slipping out, so within a few months nearly all will have escaped, mostly to go looking for food. Still, a month or two of safe keeping is enough reason for plenty of people to go hunting the wind for these tiny transparent motes.