Here are some cruel advertisements made by Jim Henson:

Hard to believe, but it apparently was a genuine ad campaign:

In 1957, Jim Henson was approached by a Washington, D.C. coffee company to produce ads for Wilkins Coffee. The local stations only had ten seconds for station identification, so the commercials had to be lightning-fast — essentially, eight seconds for the commercial pitch and a two-second shot of the product.

From 1957 to 1961, Henson made 179 commercials for Wilkins Coffee and other Wilkins products, including Community Coffee and Wilkins Tea. The ads were so successful and well-liked that they sparked a series of remakes for companies in other local markets throughout the 1960s.

The ads starred the cheerful Wilkins, who liked Wilkins Coffee, and the grumpy Wontkins, who hated it. Wilkins would often do serious harm to Wontkins in the ads — blowing him up, stabbing him with a knife, and smashing him with a club, among many other violent acts.

Link.