Bicorn and Chichevache are fabulous beasts that appear in European satirical works of the Middle Ages and Renaissance.
Bicorn is a creature—part panther, part cow, with a human-like face[1]—that devours kind-hearted and devoted husbands and (because of their abundance) is plump and well fed.
Geoffrey Chaucer mentions Chichevache in the envoy of the Clerk's Tale in his Canterbury Tales, ironically warning wives against the patience and obedience shown by Griselda in the story: O noble wyves, ful of heigh prudence, Lat noon humylitee youre tonge naille, Ne lat no clerk have cause or diligence To write of yow a storie of swich mervaille As of Grisildis pacient and kynde, Lest Chichevache yow swelwe in hire entraille!
[3] D. Laing Purves notes that "The origin of the fable was French; but Lydgate has a ballad on the subject.
"[4] In the early fifteenth century John Lydgate wrote "Bycorne and Chychevache", a 133-line poem in 7-line stanzas, probably from a French original.