Puppeteer parasites

Puppeteers are a monster based on the common scifi trope of the puppeteer parasite. Puppeteers were initially a blatant rip-off of the aliens from The Puppet Masters. When they first appeared in the 3.0 Psionics Handbook, they were depicted as ray-like creatures capable of gliding short distances like the aliens in the story. In the d20 Modern rules, they were depicted as louse-like and fed on the blood of their hosts. In the 3.5 Expanded Psionics Handbook, they lost their gliding ability and were depicted as slug-like instead. A variant known as the "flesh harrower" was introduced, which is a blatant rip-off of the aliens from Stephen King's Dreamcatcher.

Puppeteers were originally created by the mind flayers, but since the latter aren't OGL they were replaced with the phrenic scourges when Dreamscarred Press (the same authors who wrote the 3.5 psionics revision) wrote their own adventures and adapted psionics to Pathfinder. Dreamscarred Press provided further details on the puppeteers, such as the "hive brain" variant in the adventure Uncertain Futures.

Here are some in-character factoids about puppeteers to inspire your imagination:

• Puppeteers were created by the phrenic scourges for the purposes of infiltration and subversion. They are not particularly intelligent and require the occasional oversight from their masters.
• The species is divided into several specialized castes. The most common are puppeteer, flesh harrower and hive brain.
• The hive brain is responsible for reproduction and communication. 
• The puppeteer comes in at least three body types for better camouflage: slug, louse and manta ray. The manta ray form is capable of gliding short distances.
• Puppeteers subsist by siphoning harmless amounts of blood from their host. If multiple puppeteers attach to the same host, the blood loss will become harmful.
• Some puppeteers act as brood mothers who asexually spawn immature larvae, provided they have a source of biomass on which to feed.
• Some puppeteers may produce spores which grow into a red fungus known as byrum. If the byrum is consumed by a potential host, it will germinate within the digestive tract and fatally emerge as a flesh harrower. This has earned the moniker "shit weasel".
• The most intelligent and psychically formidable puppeteers are the "mind maggots". Unlike their kin, mind maggots act on their own initiative and require no orders. Indeed, some have rebelled against the scourges in favor of working as arcane familiars. Their fatal flaw is arrogance: even as a familiar they will still nudge their host in the direction they believe is correct. (see statistics in Monster Encyclopaedia II)