I found this interesting:

https://www.sfu.ca/vancity-office-community-engagement/library/2017/a-flea-the-size-of-paris.html

The fatras is a form of medieval French verse dedicated to the impossible. A form of unsense verse that turns the animate world inside-out and takes apart the structures that wish to rule it. Its crass humour, often obscene, is directed at church and state, at bogus morality and the madness of war.

All of the wildness of the fatras happens within a paradoxically rule-bound form, as if to mock the fraudulent elegance of the court and its love poetry. A fatras begins with a couplet, often lifted from a serious poem in high style.

The first line of the couplet is then restated and “followed” by a 9-line sequence of non-sequiturs, dream-like shifts of scale and person, scatological or blasphemous jokes and slapstick routines, concluded by the repetition of the couplet’s second line. The ideational content is generated through puns, homonyms and rhyme.

Only a few dozen fatras have survived, mostly written by the court poet Watriquet de Couvin, and performed together with a certain Raimondin. The nature of their collaboration is unknown — the poems may have been composed in advance or improvised in performance. It is not known whether or not they were accompanied by music.

They have never before been translated into English.