Not sure if this quite qualifies as a Halloween Horror, but it includes monsters, and it struck my fancy.
Basically, it’s an anime series focused on a guy who’s crappy job is to clean up after kaiju attacks.
It’s basically Damage Inc. meets Godzilla. Plus the teaser trailer is giving off a tiny bit of a FLCL vibe.
I don’t subscribe to Crunchy Roll (or any streaming service), but I’d seriously consider buying the DVD set when it eventually comes out.