At the end of every episode of
Mystery Science Theater 3000 from Season 2 through Season 6
Dr. Forrester would order his sidekick,
TV's Frank, to sever communications with the
Satellite of Love by telling him to "Push the button, Frank." When
Frank pushed the button the TV screen would fold to black (much like how an older
television would fade out when it was turned off) and a unique sound effect would occur with the visual. Then the credits would roll, followed by the
stinger.
The button always stayed pushed except for one episode, "Daddy-O", in which the button was gummed up with baby food. The button would be pushed, the credits would start, but then the button would pop-up, becoming unpushed, causing the screen to flip open to reveal Deep 13 and two stunned mad scientists.
The famous button was stolen from the Deep 13 set during a 1996 convention tour of the Mystery Science Theater 3000 studio. However, since the Deep 13 was scheduled to be demolished and replaced with the Deep Ape set for Season 8 of the show, the issue wasn't a problem.
Somewhere out there some dishonest (but lucky) person has one of the ultimate MST3K props.