Mind parasite
Seems odd that as generic a sci-fi concept as "mind parasite" points to one specific species from a comic. Many, many, MANY, other Whoniverse species could be described as "mind parasites", so this would be better off at Mind Parasite (John Smith and the Common Men), with "mind parasite" as an overview page for the general species classification.
Talk about it here.
- You may be looking for the parasite inside the Keller Machine.
Mind parasites were creatures that attached people's minds to themselves using their tendrils, trapping people in a dream world called the "hellscape", where the parasite "enjoy[ed] people's private horrors", and building "the worst thing [they] could ever imagine". When humans were released from the mind parasite's hellscape, they had side-effects of "nasty dreams" for a few weeks, but their minds would always be able to "bounce back".
One mind parasite, known as Mr Waites, fed off the Eleventh Doctor's pain in his hellscape, but the Doctor broke free and attached Waites' tendril to Waites' own mind, killing him. (COMIC: John Smith and the Common Men)
