Spongebob Squarepants - Magic Mustard
In the Spongebob episode where Mr. Krabs tells Spongebob never to do Karate, Spongebob and Sandy go to the park and start to make Krabby Patties. (How does Sandy know the recipe?) When Spongebob asks Sandy what she would like on her patty, she says mustard, and Spongebob then puts a bottle of mustard on the table. As he then later begins to cut the patties, one of them slides over and the mustard immediately disappears!