Jelly Demon 2.0
Probably you've always been wondering how the hell some people's bodies are so ungodly flexible? Don't believe a word when they tell you it takes "years and years of hard training!"
All you have to do is summon the demon known as the Jelly Demon who is known for sucking stiffness out of mortal spines and this demon has already been described in the following article written earlier:
Once the demon sucks out the stiffness, the one obtains the ability to bend like rubber and make a lot of money just showing off at the marketplace... But the common feeling of all so called "contortionists" who accomplished the ritual in the past and now are famous people, is the feeling "what more can I do, now?"
Yes, ultimate flexibility comes along with the realization of the ultimate limit. No matter how flexible you are, you'll never be able to bend more than in half backwards. And that's where this second (yet not final) form of the Jelly Demon comes in to help...
Only three to three and a half contortionists in the world are confirmed to have contacted him which suggests that the price is so high that almost nobody dares. At least one thing is known for sure that no mortal throughout the documented history has yet reached further than the second form of the demon.
Perhaps in the very ancient past people were able to contact even greater forms of him but they were made so flexible, nearly liquid, and slipped into the deepest holes of the darkest caves, having turned into something that later evolved into what we know today as worms and snakes...