Alice in Wonderland Syndrome.
Named after Lewis Carroll's famous novel, this neurological condition makes objects (including one's own body parts) seem smaller, larger, closer or more distant than they really are. It's more common in childhood, often at the onset of sleep, and may disappear by adulthood. The prevalence and origin are unknown, but it sometimes accompanies migraine headaches, epilepsy, brain tumors or the use of psychotropic drugs.