The Rocky and Bullwinkle Show was a 1960’s cartoon full of humor for thinking adults. That means it was loaded with puns, satire and other cerebral type humor. I thought it was the best thing on television. I still think it was one of the best comedy programs television ever produced.
This link to Wikipedia will help you understand more about The Rocky and Bullwinkle Show and Mr. Peabody. You should be able to find many of the shows on YouTube.
The “WayBack” machine was a time-travel device that would take Mr. Peabody and Sherman back in history to specific important events, such as the battle of Waterloo or Paul Revere’s Ride. Every segment of the Mr. Peabody cartoon would end with Sherman making a summary statement or question that would be answered by Mr. Peabody with a terrible pun. Thus the “terrible pun” that is offered in the spirit of the show.
I found the picture of Mr. Peabody and Sherman on another website. The picture is a link to that site. That site did not provide further credit and I did not find that picture elsewhere.