I hope to at least do one of each, as I have ALOT of ideas...)
1) Fight ~ Oc and Crush get into a fight about something. Cheating, Money problems, Romance problems, Children, whatever the reason, go nuts!
2) Death ~ OC dies, and we follow Crush as they are haunted by OC. Its not really OC, kist a drunken memory, and Crush blaming themselve. (or Vise Versa where Crush dies)
3) Nightmare AU ~ Nightmare AU, where everyone is trapped in a huge, abandoned Mansion, and is each put into their own personal hell.