Sybil Trelawney 

The act of abruptly stopping previous actions (i.e. conversation), turning one's head and looking blankly off into space after one has developed a deep thought and cannot help but interpret its meaning.

Corey: "Yeah, so I was doing my Honors Physics homework with my boyz James, Dapo, Dan, Noam, and the rest of my peepz when..." (looks off into space)
Cristina: "Yo! Corey just pulled a Sybil Trelawney in this motha!!! Whatchu thinkin' bout, Corey?"

Raven from That's So Raven has mastered the "Sybil Trelawney". Raven may try to act like she originated the gesture, but Sybil Trelawney is the original gangsta.

Sybil Trelawney by John Fan May 16, 2007

Sybil Trelawney 

A crazy divination teacher from the Harry Potter series. Trelawney is always predicting Harry's death. While most (even Dumbledore) say she's delusional and paranoid, her predictions are usually right in one way or another.

Harry: Really, I swear.
Trelawney: Yeah, whatever.

Sybil Trelawney by Melanie October 27, 2003