In its second season, The Electric Company added a superhero satire feature that would appear sporadically, with 60 installments over the next four years. The Adventures of Letterman was a series of 2 1/2 minute shorts designed to, as in the context of the Company's overall format, teach young viewers about specific words.
Every story had the same basic plot. Spell Binder has a little fun at the expense of some poor, innocent citizen, and Letterman appears, emerging from the convienent vicinity, to correct the problem. The series reunited Gene Wilder & Zero Mostel, the stars of the original feature film version of "The Producers", as the voices of Letterman & Spell Binder, respectively, with Joan Rivers serving as narrator.
NantoVision1 uploaded "In a Pickle":
During Electric Company's final season, they created a live-action parody of Letterman, Litterman. I will try to locate that skit. Of course you know that before the Company ended its first run, Spider-Man would become a part of the show. Look for Spidey Super Stories to show up before too long.
To paraphrase ESPN's Kenny Mayne back in the day, the simplicity of these cartoons amuses me. Bring me your finest meats & cheeses.