The other day I saw the following (written) phrase being used in an American TV series episode:
"Why aren't I on the list?"
Even though I know this "sounds right" (I'm a relatively fluent, although not native, English speaker), this struck me as weird, since "am" is the normal form for "I" in all/most other situations ("I am", "you are", "he/she/it is" etc), i.e. without abbreviation being used, the correct phrasing would be "Why am I not on the list" (rather than "Why are I not on the list").
So, what is the origin of this strange special case, and are there also other similar ones like it in the English language (i.e. where the abbreviated word is at the same time replaced by a completely OTHER word or word form, effectively not just being abbreviated, but rather also substituted at the same time)?