I think I've figured out the issue—it's an AirDrop bug. For me ... it's my Apple Watch Ultra v1 trying to AirDrop something to my iPhone 15 Pro Max. I have also recreated the issue with both devices not even on a multi charger. And I can replicate it multiple times.
After restarting my iPhone I was getting a message to bring "the devices" closer together to "complete the AirDrop". Though I'm not sure the message may have flashed in my Dynamic Island. And I could only reproduce it when restarting my iPhone and putting it back on the charger next to my watch.
So if I went into AirDrop settings and turned off " START SHARING BY : Bringing devices together" the "Rainbow Wave & Stars" stopped it happening on the charger. If I turned the setting back on while both devices were next to each other the wave & sound happened immediately.
I could also get the wave to happen even if both the watch & phone were off the charger and right next to one another. Very odd.
At one point I did something & the Rainbow and Stars wave was happening on the watch and not on the iPhone. WHAT???
This is definitely an Apple AirDrop issue. If you don't use AirDrop just uncheck "Bringing device's together." That will stop the bizarre problem until Apple can fix it.
And for the guy who turned his iPhone to landscape, stopping the phone wave ... that makes total sense. The phone & watch are far enough away from each other to stop the bug.
And it is a bug. I'll be calling Apple to report it tomorrow.
Funny thing is ... normally when I charge my watch & iPhone for the night I put the phone in Airplane mode so I don't get calls in the middle of the night. For whatever reason, tonight I forgot to put it into Airplane mode & the wave happened.
Pretty wild! And a bit scary too.
So y'all aren't hallucinating!
Ive been an Apple/Mac consultant for 20+ years. I do know how to troubleshoot. Took a bit to figure it out, but at least I got it to stop. 👍
