From season 2 of Heathcliff's ABC series comes this interesting short, clocking in at just over 4 minutes.
Heathcliff (Mel Blanc) becomes the target of a teeny-tiny Martian who's looking for an Earth specimen. Well, seems this little man from Mars picked the wrong target. Here's "A Close Encounter":
Near the end, when Heathcliff creates a finger puppet lookalike of the Martian, you'll notice how Blanc slips in a little dose of Marvin the Martian. Considering that WB now has the rights to this cartoon, it's no longer an issue, is it?