The “red snake of death” is an error message that can appear on an Apple Watch when it is experiencing a software issue. The error message is accompanied by a red snake icon, and it indicates that the Apple Watch needs to be restarted. The red snake of death can be caused by a variety of factors, including software updates, app installations, and hardware problems.
If you see the red snake of death on your Apple Watch, you should try restarting the watch. To do this, press and hold the side button and the Digital Crown at the same time. After about 10 seconds, the Apple Watch will restart. If the red snake of death persists after restarting the watch, you may need to contact Apple Support.