A topic I’m studying now from a mental model perspective is that of “Otherkin”. Don’t know what it is? You aren’t alone. It’s a sub-niche movement of people who believe – not pretend, but actually believe – they are partially, or entirely, non-human. Some think that they have been reincarnated with the soul of an animal, dragon, fairy, plant, alien, cartoon, demon, angel, elf, vampire, etc. Some believe they actually are partially these things biologically.