Frequently washing your hands is one of the best defenses against contracting (and spreading) the coronavirus. Google already came up with a horrible song for timing your hand-washing, but if you have a Wear OS watch, you'll now receive periodic reminders to get scrubbing.
The Clock application on Wear OS is now sending periodic alerts to wash your hands. When the alert is opened, a timer for 40 seconds is started, with a reminder to always use soap. When the timer is completed, the app will tell you that another alert will arrive in three hours.
The feature seemed to arrive as part of the v5.4.0 update, so check your watch's Play Store if you haven't seen it yet. If you don't need to be buzzed every three hours, the reminder has its own notification channel, so you can disable it by holding down on the notification.