The fake Rahm twitter feed @MayorEmanuel, took notice of the picture I posted earlier Sunday of a young Rahm Emanuel in his ballet tights (from Sun-Times political writer Abdon M. Pallash's story about mayoral candidates as youngsters). I can't tell you what he said because he uses the F word too much and I hesitate to use it on my blog. Anyway, @MayorEmanuel challenged me to a dance off. And if it is to rock and roll tunes....maybe I'll do it.

Anyway, Emanuel told Sun-Times columnist Richard Roeper on his radio show that he would make a donation to charity if the fake Rahm would reveal his or her identify.

Roeper wrote on Feb. 16: "In the Twitterverse, there are two main Rahm Emanuels -- the actual candidate for mayor, and the guy or gal who's been doing an extended, obscenity-riddled, hilarious impersonation of Rahm on Twitter since last September."

Follow Lynn Sweet on Twitter: @LynnSweet