heres a little info i got from wixapedia .....Marvel Comics' Impossible Man seems to have been modeled after Mxyzptlk, and writers at DC have suggested that the two characters are one and the same: in Superman vol. 2, #50, Mxyzptlk mentions that he's been "having fun with my new fantastic friends" and later mentions getting "back to my four new friends", referring presumably to the Fantastic Four; he also uses the expression "it's blubbering time" (a play on the Thing's standard battle-cry "it's clobbering time"), and says that he's been having "a backlog of mayhem in another dimension", probably referring to the Marvel Universe. Mxyzptlk keeps altering his form constantly in this issue, and also changes into a form similar to that of the Impossible Man, with inverted colors, and says "Sometimes it's just impossible to remember what I look like from world to world." Writers at Marvel, however, clarified this in the Impossible Man's entry in the 2006 edition of the Official Handbook of the Marvel Universe, noting that Mxyzptlk was merely impersonating Impy.
Later on, in 1996, the Impossible Man and Mxyzptlk teamed up in the DC/Marvel crossover story Silver Surfer vs. Superman, in which the two imps combined their powers to swap universes for the Silver Surfer and Superman. Here the power of Impossible Man was more like Mxyzptlk's own reality warping powers, rather than just shapeshifting.[citation needed] In this comic, Mxyzptlk and Impossible Man have a fight where they keep changing into various characters from their respective universe, for instance The Incredible Hulk and Doomsday. The differences are profoundly displayed between the two characters - chiefly, in that Impossible Man's motive is pure fun and abhors true violence, while Mxyzptlk is darker and more interested in destructive chaos, and to Impossible Man's astonishment and anger, is prone to lying.