Lethal electric fences, however, use a continuous current that can make a person lock on to the wire as voltage causes involuntary muscle contractions, paralysis and death.

WSJ: Escape From a North Korean Prison

In the Alabama case, a consumer took Reglan and developed tardive dyskinesia, which causes incurable and involuntary muscle movements, and accused Wyeth, which is now owned by Pfizer, of failing to warn of the risk of long-term use.

FORBES: Pfizer Wants Court To Rehear Generic Labeling Case And Avoid Tort Hell

People who regularly get writer's cramp may be suffering from dystonia, a definition applied to a wide variety of conditions in which people suffer involuntary and often painful sustained muscle spasms.

BBC: writing