Obeliscolychne
It's the insult of all insults. It's like being called a lighthouse, but you're also getting called a bad lighthouse.
He says: "You’re an obeliscolychne. I swear I’ve seen better lighthouses in a fishbowl."
She tweets: "My dog just called me an obeliscolychne. I’m gonna give him a time-out."
He DMs: "You’re an obeliscolychne. I’m gonna rename my pet lighthouse after you."