Supergirl has cast Once Upon A Time actor Peter Gadiot as Mr. Mxyzptlk, the classic Superman villain who is an imp from the 5th Dimension, according to Entertainment Weekly.
In comic books, Mxyzptlk often sets up elaborate scenarios and pranks to vex the Man of Steel, only returning to the 5th Dimension when he is forced to say his own name backwards. It's not clear how closely Supergirl's version of the character will tie to his comic book counterpart.
Gadiot will reportedly appear in two episodes of Supergirl, though it's not known in which episode he'll make his debut. Supergirl airs Monday nights on CW.