Diss For Sale!

So this is a particular one I just came up with in like the last 5 minutes.

This diss is to be deployed, to my imagination, when you're talking to someone, say for example, saying something that is quite serious and they reply with something that just makes you think, 'Dude, just try for 2 minutes to not exhibit an IQ of -3'.

So anyway, this is how it goes.

You say your piece, the diss-ee reacts in a completely bizarre way and says something completely unacceptable. Right?

You, my friend, in response, start looking around, as though you've lost something.

Repeat this until the diss-ee cannot help but ask you 

"what are you looking for?"

Respond with, 

"Your brain. Pretty sure you had it a minute ago."

You're terribly welcome.

*Leaves audience full of standing ovation*