Constantine is the world's "Number One" criminal and adoppelgänger of Kermit the Frog. Along with his sidekick Dominic(aka "Number Two"), Constantine sets out to steal an enormous diamond in Muppets Most Wanted. However, mayhem ensues when he gets entangled with the Muppet troupe on their European tour.
He is almost identical to Kermit aside from a few details. His pupils are shaped like Kermit's, but are slanted in toward each other at a sharper angle. Kermit's signature 11-point collar is duplicated, but Constantine's is notably shorter. The most distinguishable difference is a beauty mark on Constantine's face that he has covered up. Kermit is seen with the beauty mark while detained in a Russian prison, presumably mistaken for Constantine.