She kept her co-stars laughing
As you might imagine, Lucy’s co-stars had to stick to a contract with all sorts of strange stipulations if they wanted to remain on the show. Vivian Vance, who played Ethel Mertz, was forced to stay at least 20 pounds heavier than Lucy throughout the series. While this might have been frustrating to Vivian, she and Lucy shared a laugh about it on a talk show years later.
They retold a story where Lucy came up with a mock contract for Vivian, stating that she would have to gain five pounds every week nonstop. After 179 episodes together, according to the contract, Vivian would have to wear over 900 pounds!