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Well, this is bizarre: Miley Cyrus and Sinead O'Connor are in a full-blown feud following their online tiff yesterday.

Sinead got wind of Miley's dismissive response to her online letter on Thursday night and immediately bit back hard. In a vitriolic Facebook post, O'Connor accuses the pop star of "bullying" her by "mocking mental health issues," which O'Connor openly struggles with.

This all began when Sinead wrote Miley an open letter warning Ms. Montana that the music industry was trying to turn her into "prostitute" and "nothing but harm will come in the long run."

Cyrus dismissed O'Connor's letter by posting a Twitter rant the Irish singer wrote while struggling with mental illness two years ago. Cyrus also derogatorily compared O'Connor to Amanda Bynes, the former Nickelodeon child actress who famously spent most of this year melting down in the public eye.

After Miley's Bynes comparison, Sinead took the gloves off. "Ms. Cyrus posted tweets which I sent when I was ill and seeking medical help," she wrote, adding the threat, "Her lawyers will be contacted by mine regarding this matter." O'Connor correctly called out Cyrus for gleefully making light of her mental health struggles, writing, "I do not condone the abuse or mockery of those brave enough to openly discuss mental health issues. Mockery causes death. It is an unacceptable form of bullying."

Sensing the exchange was getting out of hand, Cyrus tried to turn the public discussion private. "If you'd like to meet up and talk, lemme know in your next letter," Miley tweeted

At this point, we were easily on Sinead's side. Cyrus was out of line for mocking her mental health struggles. But here's where things took a turn for the ugly. Instead of taking Miley up on the offer, Sinead continued her open rant and very inappropriately predicted that the 20-year-old will inevitably end up struggling with mental issues or addiction.

"I have no interest in meeting you," O'Connor wrote in a second Facebook post. "When you end up in the psych ward or rehab I'll be happy to visit you."  

Yikes. Sinead had the upper hand, but this amounts to the same sort of casually mockery she was complaining about just one post earlier. Still, we have to agree with O'Connor's final point: "When you publicly apologize to Amanda, myself and all mental health sufferers, that will end the matter."

Hopefully Miley will do just that and this strange, bizarre feud can end.