Thoughtforms that Manifested into Entites

Hey occultists, magicians, and witches. Any of you guys ever look into thoughtforms, egregores, or tulpamancy? Ever see a fictional character become an egregore you could summon?

Oh boy, does it happen. By now I'm sure you've heard of creepypastas, in particular; Slenderman. If you havn't, you're living under a rock. So for all intents and purposes, Slenderman was a fictional character, an imagined idea to scare the crap out of people on the internet. All good fun. But if you know anything about the psychic power of human consciousness, you know that we can create entities if devoted enough.

Boom, the Slenderman egregore began to take shape. Back at the height of the creepypasta craze (hardcore fans dont come for me lol), I watched several friends of both sound and unsound mind be scared out of their wits by this character, and the online legends surrounding him. One girl in particular stopped sleeping, she was so terrified of him appearing in dreams. Some of us were even convinced that he was a real mythological figure, in particular, a faery. Now I know my friend group wasn't unusual. Tons of people all over the country, hell maybe even the world were entranced by Slenderman and his urban legends. All that attention. all that focus. all that raw, emotional human fear. That energy had to go somewhere. And with a unified mythology and visual representation, we were all, thousands of us, all putting energy into this creature. 

Fast forward a few years, and I'm talking to occultists on discord. We were discussing what got us into the occult. One guy, let's call him Sam; Sam said he started through creepypastas. That he tried to summon Slenderman and it actually worked. Now Sam was looking for ways to banish the spooky fucker, with minimal success. No amount of sage, no amount of rounds of the LBRP, no number of sword slashes from an archangel's blade could fully cast out this thing. This creature, this egregore acted like the character, with a few new behaviors. The most notable behavior would be how this tall, no-faced apparition would suck the energy out of a person. Sam would feel weak after seeing it. Sometimes he would get sick. Nightmares with Slenderman in it would leave Sam feeling exhausted in the morning. This thing was absolutely psychically feeding off of him. To this day, Sam still hasn't found a way to detach from this thing.