A madman whose mother, Occassion, encouraged him to attack passing knights. Sir Guyon came across Furor beating the squire Phedon. Guyon bound and gagged Occassion, and captured Furor.
Guyon later allowed the brash knight Pyrochles to free Furor, who beat Pyrochles to unconsciousness.
Source
The Faerie Queene | Edmund Spenser, 1570-1599