A troubled Amanda Bynes took to twitter yesterday to insult Rihanna. "Chris brown beat you because you're not pretty enough," she wrote. "No one wants to be your lover so you call everyone and their mother that I almost named my dog Rihanna."

The offensive tweets were quickly deleted but not before TMZ could take a screen grab.

Did Rihanna ignore the low blows? No way. "Ya see what happens when they cancel intervention?" she retorted.

An incensed Bynes replied, "@rihanna unlike ur fugly faced self I don't do drugs! U need the intervention dog! I met ur ugly face in person! U aren't pretty u know it!"

Read the rest on TMZ