clownback
If someone says "clown on you" to you and you say "clown on you" back that's called a clownback. Typically there's a "No clownbacks" rule so if you clownback you'll probably get an angry "No clownbacks!" response
John : Hey Jim, clown on you!
Jim : Well, clown on you John!
Dave : No clownbacks asshole
Jim : Well, clown on you John!
Dave : No clownbacks asshole