A Tulpa is kind of like an imaginary friend times ten. A tulpa is a controlled hallucination of a creature (human or not) that is sentient and different from you. It takes a lot of time and effort, but when your Tulpa is complete, he/she/it will be able to communicate with you, argue, dissagree, and you will have not control over it. It will become it's own creature and will change itself (probably), but you can still summon or hide it at will. It may have different tastes than you in music, art, climate, and many other things. It is it's own sentinent being and therefore has it's own opinions and moral values. It becomes a sort of companion, and you can teach it to access your conscience so it can reveal to you things your conscious mind may have forgotten. Useful and great friends, Tuplas are just... really cool. One man has a Tulpa with a microwave head, others have made ponies, furries, or versions of themselves.

Look it up on Google, find out more! Tulpas are really interesing things, and maybe you might want to create your own!