Amanda Bynes Rihanna-Bashing Tweets Were Fake!

Amanda Bynes is now claiming the tweets bashing Rihanna (pardon the pun) did not come from her and were actually mocked up by someone else ... then she went on to say some other crazy stuff.

Bynes went on another rambling Twitter run this afternoon, in which she says, "I saw a bunch of mocked up tweets about me bashing Rihanna in my mentions. I'm followed by so many people that someone is always mocking up fake tweets so I feel the need to address them!"

From there she goes on to say ... well, your guess is as good as ours:

"That's one of the mocked up images, they took photos of me from outside and morphed them onto someone else's body. I am allergic to marijuana and alcohol but I smoke tobacco. Why does Rihanna smoke weed and not get in trouble for it but I smoke tobacco and people think I'm on drugs? I refuse to be treated like someone I'm not, which is why I fought for myself and am suing everyone involved. I don't need to go to rehab. There is never a drug or alcohol in my system! I'm sick of all the lies! What would you do if someone accused you of things you didn't do and yet you still had to be in jail at all over it! I'm so offended but I am so educated that I know cops cannot illegally enter my apartment, sexually harass me, arrest me, take me to a MENTAL HOSPITAL, then lock me up for a crime I didn't commit. I'm suing them all for this upsetting nightmare. My lawyer knows I'm a model citizen who doesn't partake in drugs. He's going to court this week to set the record straight again on my behalf. Thankfully I'm an educated multi-millionaire who knows better than to speak to perverted unjust cops without my lawyer."

Amanda Bynes to Rihanna 'Chris Brown Beat You Because You're Not Pretty Enough'

Amanda Bynes just inexplicably railed on Rihanna on Twitter, saying Chris Brown beat her because she's ugly ... but RiRi got the last word and it was AWESOME.

Bynes tweeted -- and quickly deleted -- "@rihanna Chris Brown beat you because you're not pretty enough."

She followed that up with another insult -- about wanting to name her dog Rihanna. It's unclear what set her off.

RiRi clearly got wind of the deleted tweets, because she just posted the BEST COMEBACK EVER:

Don't mess with RiRi.

UPDATE 11:03 AM PT -- Amanda has already responded (and already deleted):

"@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!"

Rihanna vs. Amanda Bynes Who'd You Rather?

Before she called her ugly on Twitter, Amanda Bynes posed with Rihanna at the CFDA Awards in New York City ... way back on June 5, 2006.

The question is ...