Here's a fun fact about the Kroffts:

McDonalds hired an advertising agency, who reached out to them to create the McDonaldland characters (Grimace, Hamburgler, Mayor McCheese etc.) based on their H.R. Puffinstuff characters.

They did as asked, and created the characters and were all seen and pictures taken of the costumes. Then the agency called the Kroffts and told them the Mcdonalds ad campaign had been canceled.

The agency actually used the pictures they took and hired former employees of the Kroffts to create the sets and costumes and even hired Krofft's voice actor to do several of the voices for their commercials.

The Kroffts sued. Initially were awarded $50K. They appealed the judgement and were then awarded $1.04M on appeal.