So, here's an internet community I'd like to talk about: tulpamancers.
A few weeks ago, a friend of mine posted the following status on Facebook: "thinking about Tulpas and how they're the scariest concept I've ever heard of." She then linked to this sub-Reddit, to which I recommend you dedicate several hours of your time. It's by and for people who call themselves "tulpamancers," people who purposefully create "living," "sentient" voices in their heads. These "tulpas" are considered sentient beings that happen to live within the same body as the tulpamancer. Or, as Reddit tulpamancers put it in their FAQ: