There is a technique in composition where certain notes in a familiar melody are entirely skipped, so that they are not played but are still imagined. This usually happens (or is noticeable) in the later stages of a piece, when the melody has already been introduced and is being repeated. It could also be used with a melody that is previously familiar to listeners.
What is this technique called, and what is its intended effect?
I'm not a musician so I don't know the technical details, but I found the terms "pensato" and "melodic expectation" that seem to describe the mechanics of it.