A couple of years ago I invented a form without being quite aware of it. I wrote a poem consisting mostly of lines lifted from other sources with exactly one letter changed in each lifted line.
The poem began, "A thong of beauty is a joy forever." Other lines included "'Dope' is the thing with feathers" and "'Deaf' was all he answered." (Thank you, Keats, Dickinson, and Frost.)
You get the idea.
Some might think this a sophomoric parlor game, and maybe it is, but you can say that of a lot of parlor games and of, too, a lot of embryonic forms and literary sub-genres, and this may be another case of the undervalued asset, limericks and puns being two others. Anyway I invented it.
I would love it if readers proposed examples.
My line of the day is from Auden.
"We must love one another or diet." -- DL