Remember not to enter the monastery; those monks can be real moutons enragés.
First attested in 1826. From Frenchmouton enragé (“angry sheep”), a nickname given to French politician Nicolas de Condorcet by Turgot. Formed from mouton (“sheep”) + enragé, past participle of enrager (“to enrage”).
English Wiktionary. Available under CC-BY-SA license.