Amanda Bynes unleashed some serious fury on Rihanna via Twitter today, calling the singer "ugly" and hitting her below the belt with a reference to her infamous abuse scandal with Chris Brown. "@rihanna Chris Brown beat you because you're not pretty enough," Bynes tweeted, going on to say, "@rihanna no one wants to be your lover so you call everyone and their mother that I almost named my new dog Rihanna." Bynes quickly deleted her tweets…but it looked like Rihanna had already caught wind of the Easy A actress's insults when she wrote this just moments later: "Ya see what happens when they cancel Intervention?" And even without a Twitter mention from Rihanna, Bynes got the message, firing back with,"@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!" The duo's feud stopped there, with Rihanna making no other comments in reference to Bynes...at least for now. cr:E!