Amanda Bynes unleashed some serious fury on Rihanna via Twitter on Sunday, calling the singer "ugly" and hitting her below the belt with a reference to her infamous abuse scandal with Chris Brown.

As usual with Amanda Bynes, it was all for no apparent reason.

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Here's what Bynes tweeted:

"@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 the tweets from her account, but it looks like Rihanna had already caught wind of the insults when RiRi wrote this just moments later:

"Ya see what happens when they cancel Intervention?"

Source: E! Online