That point of sleep where you realise that your arm is sticking out of bed and therefore susceptible to being grabbed by Freddy Krueger or similar that has been waiting under your bed until you fell asleep. Symptoms include leaping, gasping, rapid heart beat, withdrawing vulnerable arm, wrapping body tightly in protective bedsheets.
This
syndrome was created by excessive watching of
horror flicks, usually at a socially unacceptable
age.