Have you ever discovered that your version of a song's lyric is a bit different to the actual one? For example, a lot of people heard Police's "Message in a Bottle" as “A year has passed since I broke my nose.” But Police sang it as “A year has passed since I wrote my note.”
When this happens, it's known as a mondegreen.
It also applies to mishearing or misinterpreting words or phrases other than from songs.
Oh my - I have just come across this thread and you have me laughing ... I can say which was my favourite but nullibiquitous came close along with Mona's suggestion of it describing kids' homework! As a English Tutor I have been looking everywhere for this. Nullibiquitous too is the help you need 3 days before Christmas when the kitchen is breathing fire because it's your turn to entertain the extended family including all the cousins AND Uncle Scrooge.
Other words that come to mind that sort of fit with this theme are portmanteau words - words made up of two others which produce new meaning. Properties and Opportunity (used by a real estate person) become 'Propertunites' or a good one I saw as a business name in the UK 'Shoeligans' ... a children's shoe store. There are so many more, I used to collect them - have just gone blank.
Anyway I am going to go over these words above and see how many I can use - thing is, with the dumbing down of everything, so much is being lost because many are happy with the few words used in an everyday life so why use more?