Otto's irresistible dance

Otto's irresistible dance is an enchantment spell that forces the subject to dance. It was presumably developed by Otto.

Effect
The subject feels an undeniable urge to dance and begins doing so, complete with foot shuffling and tapping. The dance makes it impossible for the subject to do anything other than caper and prance, worsens the Armor Class of the creature by -4, makes Reflex saves impossible except on a roll of 20, and makes it impossible to use a shield.