Suggest me a dark beach read

When I'm vacationing at the beach, I like to read moody and/or atmospheric books that are set mostly by the sea. Some I've enjoyed:

The Sea, the Sea by Iris Murdoch

Tapping the Source by Kem Nunn

Less Than Zero by Bret Easton Ellis

Play it as It Lays by Joan Didion (not necessarily set at the beach, but novels set in pre-2000s California seem to scratch that itch)

Picnic at Hanging Rock by Joan Lindsey (also not ocean-related but definitely atmospheric)

Any suggestions are welcome! Especially any books with horror/weird/surreal/an-old-mansion-is-crumbling vibes.