Unlike his "Pigs in Space" costars Link Hogthrob and Miss Piggy, elderly mad scientist Dr. Julius Strangepork (originally voiced by Jerry Nelson) rarely appeared in other sketches on The Muppet Show.

But this is less about Kermit than about a science teacher who has weird trauma from refusing to dissect a frog when he was younger. The film’s only edge is that all the muppets are nude, ...