Tetanus is a medical condition caused by a toxin produced by Clostridium tetani bacteria. It is characterized by prolonged contraction of skeletal muscle fibers. The toxin enters the body through breaks in the skin like wounds, burns, or puncture wounds. Incubation periods can last up to months but symptoms usually appear within 2 weeks. Generalized tetanus is the most common type and causes painful muscle spasms, lockjaw, and stiffness. It can be life-threatening if not properly treated with a tetanus immunoglobulin and antibiotic like metronidazole.