Every once in a while, my watch will vibrate and then the center of the screen will start glowing like this. I’ve seen it on Lunar and Modular. I don’t know what it means. Any clues????
You are bringing the NFC chip in your phone close to the watch and it's doing the NameDrop animation. See https://support.apple.com/guide/iphone/namedrop-iphone-share-contact-info-iph1b6c664b7/ios