Has an active online community.
13 oddities.
A pleasant tingling that starts on the scalp and moves down the neck and spine, set off by whispering, tapping, soft sounds, or gentle personal attention. Not everyone gets it. A large online community is built around it.
Small visible twitches in the eyelid, calf, thumb, or arm that come and go with no weakness. About 70% of healthy people get them. They are not a sign of nerve disease.
The world suddenly seems flat, distant, or like a film (derealization), or you feel like you are watching yourself from outside (depersonalization). Most people have a brief episode at some point, usually under stress.
About half of all people can make a low roar inside their own head by tensing a tiny muscle in the middle ear.
Goosebumps and a wave of chills down the back at a powerful moment in music, a film, or a speech. About half of people get it regularly. It comes from the brain's reward system reacting to an expectation being met or broken.
A kind of dream, usually during fever in childhood, filled with huge or tiny shapes, infinite space, crushing pressure, and dread. The name comes from an online forum, not a medical text, but each piece of it is well known to neuroscience.
Some people have never burped in their lives. Gas cannot pass a ring of muscle at the top of the food pipe, so it stays trapped. This causes gurgling, bloating, and painful pressure. Since 2019 it has a name and a treatment.
You wake up, or start to fall asleep, and cannot move or speak for a few seconds to minutes. Sometimes a threatening presence seems to be in the room. It is the normal paralysis of dreaming sleep running a little late.
In some people, one sense triggers another. Letters have colours, sounds have shapes, or days of the week sit in fixed places in space. The pairings are automatic and stay the same for life.
A ringing, hissing, buzzing, or roaring sound with no source outside your head. Between 15% and 20% of people have it. It is mostly the hearing system filling in for damaged or tired inner-ear cells.
Small white or yellow lumps that form in the folds of the tonsils and sometimes come out when you cough. They smell bad and feel like something is stuck in the throat. They are harmless.
Tiny flickering dots across the whole field of vision, like static on an old TV, present with eyes open or closed. About 2–3% of people have it. The eyes are fine. The visual part of the brain is over-active.
Giving yourself goosebumps on command, without music, cold, or fear. About 1 in 1,500 people can do it. The muscles involved are not supposed to take orders.