A man in China was living with a five inch long tapeworm in his brain for over ten years. That’s some nightmare fuel right there. Take a look at this thing.
Apparently, the man, named Wang, enjoyed eating snails and, because they were under-cooked, he contracted a Spirometra tapeworm. Spirometra infections do not typically attack the central nervous system or the brain but they had in this case.
Wang ate the snails in 2004 and they were just now removed. Without having noticed any symptoms for a year, Wang started to notice strange tingling sensations in his arms and legs and began having convulsions.
Doctors told him the worms would continue to eat his brain until they were removed in 2018. At that point, they had been in his body for fourteen years!