T-shirt I got for Christmas:

No doubt you all already know all about tulpas, but if not, here’s Wikipedia:
Tulpas are “magic formations generated by a powerful concentration of thought” . . . Once the tulpa is endowed with enough vitality to be capable of playing the part of a real being, it tends to free itself from its maker’s control. . . . David-Néel claimed to have created a tulpa . . . which later developed a life of its own and had to be destroyed.[ David-Néel raised the possibility that her experience was illusory: “I may have created my own hallucination”, though she reports that others could see the thoughtforms that have been created.
Who knows if I’ll ever use this concept in fiction, but obviously it has plenty of potential. At least I can nod knowingly if I see someone wearing this t-shirt. And now, so can you. You can get a t-shirt like this online, incidentally, for example here. This t-shirt was created by Ken and Robin of “Ken and Robin Talk About Stuff” — a podcast — on the grounds that vampires and zombies are so, so, so over and tulpas would be a neat replacement if we’re looking for a new fad in supernatural creatures.
So far I’ve worn this t-shirt in public twice. So far no one had asked me what a tulpa is, nor has anyone nodded knowingly. I may wear it to work — not that it’s normal work attire, but on some appropriate occasion — because I have one coworker who might recognize the word and might even nod knowingly.