House ad for The Three Mouseketeers #1 (March-April 1956); printed in Sugar and Spike #1 (April-May 1956)
Ad script, art and lettering by Sheldon Mayer
Yes, Disney gave the world the word "Mouseketeer" first, but not by muchThe Mickey Mouse Club premiered November 1955, and The Three Mousekeeters #1 was released January 19, 1956. Given the lead time in production of comics and TV series, it's likely both Disney and Mayer developed the term separately. Talk about your laws of parallel development!