Check out these two mashups from Deviant Artist Rahzzah. Each one of these is spectacular, and I feel like neither of these feel forced. Sometimes mashups can just be a combo of multiple things, but he takes the best of both properties and goes all out. Bravo sir.
The first one we have is a mashup featuring Cyclops and Wolverine being portrayed by Beeker & Animal of The Muppets. Wow... could these characters be any better cast? Animal is the perfectly obvious choice for Logan, but I think Rahzzah really hit the nail on the head with the over sensitive and borderline prissiness of Beeker as Cyclops. Magnificient.
Next up we get a mashup between the X-Men and The Breakfast Club. Honestly, Rahzzah knocked this one out of the park again. Wolvie is perfect as Judd Nelson, and you gotta love Cyclops as the douche jock that was portrayed by Emilio Estevez. This is what a mashup should be!