"Sick burn!"

(Other definitions for ouch that I've seen before include "Ow!" , "response to a bad pun" , "Pained exclamation" , "Pained cry" , "sounds painful" .)

(Other definitions for diss that I've seen before include "On the street, treat with contempt" , "Eastern town" , "Algerian grass" , "Norfolk town" , "East Anglian town" .)