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We didn't see this one coming ...

Amanda Bynes lashed out at an unsuspecting target Sunday on Twitter -- Rihanna!

The troubled former actress began by Tweeted at the singer: "@rihanna you look so ugly tryin to be white." She deleted the post two minutes later. Then she started up again, claiming Chris Brown assaulted Rihanna (referring to the 2009 incident), because she's not attractive: "Chris Brown beat you because you're not pretty enough."

Then Amanda re-Tweeted a post by Rihanna that read: "'Look who came to see me!! My lover Stella McCartney!!!," to which Bynes replied, "No one wants to be your lover so you call everyone and their mother that I almost named my new dog Rihanna."

And to that, Rihanna responded, "Ya see what happens when they cancel Intervention," referring to the popular reality show.

Then, perhaps the most ironic Tweet of all, from Amanda: "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!"

Is Amanda jealous because Drake murdered Rihanna's v**ina hooked up with Ri way back when?