The Apple Watch has a feature that ejects water from the watch’s speaker when you turn the Digital Crown and The Slow Mo Guys made a slow-motion video of it in action. According to Apple’s support site:

When Water Lock is on, your Apple Watch Series 2 or later doesn’t respond to touch on its display. This prevents accidental input while you’re in water. When you turn off Water Lock, your watch ejects any water that remains in its speaker.

My Nintendo Switch has a similar feature, only instead of turning a dial to eject the water, you hit it with a hammer until all the water leaks out. The feature only works once, though, and kind of voids the warranty.

Keep going for the full video.

Source: Geekologie – Slow-motion video of an Apple Watch ejecting water