The organs are painted on the tight, colorful body suit worn by the superhero of children’s health, Slim Goodbody, a regular on “Captain Kangaroo” and — at 54 — still going strong.

The teen looks puzzled. Jim screams, “Eat me!” Massive teeth crunch into his body. There’s a quick edit, and we see the Slim Jim logo; the crazy, screaming Jim-thing smashes his face through ...