Klaus appeared in a 2009 episode of Sesamstrasse. He tried to eat a some of the delicious salad that Samson had made for the dinner that he, Nils and Frau Kowalski was having. Nils invited him to eat with them, but it turned out that Frau Kowalski are afraid of mice, so he was asked to wait outside until they finished. However he tried to get back in, and Frau Kowalski got so scared that she tore her pearl necklace. Klaus was able to get all the pearls and Frau Kowlaski thanked him by offering him a seat at the table.

The mouse puppet was previously used as Manni in a 2008 episode.