Jack Skellington is a character and the main protagonist of the 1993 film The Nightmare Before Christmas. Jack is the "Pumpkin King" of Halloween Town, a fantasy world based solely on the Halloween holiday.
There are roughly one-sh*t billion tropes so PLEASE look through them before adding one. Otherwise add what you like. ADDITION: PLEASE read through the trope description provided before submitting something. It's not a huge deal but too often people submit characters that don't fit just because they misinterpreted the title...