The Stop Watch is an item that appears a few times in the Mario series. It would make its first appearance in Super Mario Bros. 2 after Mario or friends pull up four large vegetables. When they are pulled up, they will appear for a short second before everything in the level freezes. This will allow them to defeat enemies with ease or collect the small hearts on screen. If they touch an enemy, it will still harm them.
It would appear next in Paper Mario. When it is used in battle, it will immobilize enemies for a few turns if it is successful. It can found at most stores. It would be a rare item in Paper Mario: The Thousand-Year Door as it can only be purchased in Twilight Town or Fahr Outpost. Enemies will be able to use this item against Mario and his partners.
In the Nintendo Comics System story Cloud Nine, the Stop Watch is an animate object that will act as King Toadstool's alarm clock. It allows them to dodge the grumpy King's attempts to swat him and run to Princess Toadstool for safety.