horror show
1. Literally, a (potentially frightening) film or television show with supernatural and/or macabre elements. I can't watch these horror shows before bed, they give me nightmares.
2. Something disastrous, disorganized, or otherwise unpleasant, often said with a note of dismay or disdain. Oh boy, that performance was a real horror show. How many people were actually singing the same thing at the same time? I can't have anyone come over right now—I just got back from a business trip, and my house is a horror show!