3rd Rock from the Sun - Season 6, Episode 19 - The Thing That Wouldn't Die (1)

Mary is having some trouble dealing with what she saw: Dick transforming Scoochie into a monkey. Dick inevitably tells her the truth and she has a hard time to believe in it. Eventually she accepts it and even becomes fascinated by it. When everything seems to be going fine for Dick, Harry announces that their mission is over and they are to leave Earth.