Mordenkainen's involuntary wizardry

Mordenkainen's involuntary wizardry was a spell that forced a target spellcaster to produce the effects of a random known spell.

Effects
The spell could target any spellcasting creature within a range of 60 ft (18 m). One spell known to the target simply took effect, without requiring any action from the target, and without requiring the target to expend any components (although any necessary consumable components in the target's possession disappeared nonetheless). If the circumstances did not allow for a particular effect to happen, the spell caused damage to the target instead, proportionally to how powerful the random effect would have been.

Components
The spell required verbal and somatic components.

History
The Oerthian wizard Mordenkainen introduced the spell to Elminster and Dalamar of Krynn during one of their meetings in the house of Ed of the Greenwood on Earth.

By the mid-14 century DR, the spell was known in Faerûn as belonging to the incantation school of magic.