Not a mixed idiom or a Malaphor, but an Escher Sentence.
Spotted by @Glibkid, in a Twitter thread from @AgnesCallard featuring @fermatslibrary.
What is an Escher Sentence?
An Escher sentence is one that initially seems acceptable, but upon further reflection has no well-formed meaning. e.g. “More people have been to Berlin than I have”.
