The idea is to take existing Marvel characters and merge them with comic characters from other comic companies except DC. Also, remember to list the name of the non-Marvel company.
If a character once belonged to DC but is now owned by another company, they are fair game. The same applies to Marvel characters owned by another company, so long as it isn't DC.
Eddie Brock/Venom + Marshall Ward/Radiant Black (Image Comics) = Eddie Ward/Black Void, a disgraced journalist now given a second chance.