Justin Bieber Taunts Alleged Baby Mama Mariah Yeater via Twitter

It's been nearly six months since we've heard a peep from Mariah Yeater, the girl who claimed to have birthed Justin Bieber's baby -- but The Biebs resurrected her yesterday via Twitter ... with a little help from Borat.

Yeater's case was tossed out of court and she's been radio silent since last November, but Bieber decided to call her out anyway.

The Biebs tweeted, "Dear mariah yeeter...we have never met...so from the heart i just wanted to say..." and then he linked to a video of Borat saying "You will never get this" over and over.