If I recall correctly, and I could be wrong, Crist first went independent, then registered as a Dim.
He went "unaffiliated" to finish his campaign, then became a Democrat after the general election;
his formal coming out was at the 2012 Democratic National Convention, sort of, but he announced
his official party switch later in 2012.
Crist ran for his old gubernatorial job as a Democrat in 2014 and lost, making him the holder of a rare
triple crown: he's lost Florida general elections as a Republican, a Democrat,
and an unaffiliated
candidate.