They really need to get better ad people into their tourism board.
This trope is about when a normal, even welcoming sign is painted, sprayed, or scratched over with a warning or other apocalyptic apocrypha in order to raise tension. Usually involves replacing letters and words.
- On the poster for The Crazies.
- Batman Returns has Selina do this after surviving a murder attempt (and getting pushed to the edge of sanity) by breaking the letters in the neon sign in her room. It goes from "Hello there!" to "Hell here!"