Leg Cramps or Muscle Cramps

A sudden, abrupt, or spontaneous contraction of a muscle causing extreme pain persisting for a duration ranging from seconds to minutes resulting in residual discomfort and soreness in that muscle.

A leg cramp that usually occurs when you're sleeping, which causes so much pain you wake up and scream cusswords loudly.

or Charley Horse

A stiff and painful cramp in a muscle.

Usually due to a lack of potassium, it's when your leg tightens up, causing an extremely painful sensation. Immediatley after it's over, your leg feels really good, though.

when someone hits you in the leg with a nuckle causing a very painful cramp

a horse named Charlie, had his leg spazz out, so every time someones leg spazzed people called it a Charlie Horse. Charlie was the laughing stock so he became a rogue horse.