Sorry. Can’t believe I forgot to finish up my comments on the “Mrs. Yannes gets coupon valentine” series, which you can read here. (You might want to read the strips first because “here thar be spoilers”.)
So Morty Muffler was not just a ridiculous mascot, he was based on a real person – a long lost (and now deceased) love of Mrs. Yannes. Once you get toward the end of the series, you see that Mrs. Yannes was the basis for an anthropomorphized spark plug. You’d have thought I had that tidbit in my head as the ending all along…and you’d be be wrong. It wasn’t until I started writing it out (this is way before drawing), that this visual joke occurred to me. A really stroke of luck.