Yeah i know its what u get when a gym is atacked. But this is no gym!
You must have checked a gym where you have a mon defending. That gym is under attack. In my own experience, if you view a gym long enough via a mon that is defending it is under attack you will get this visual bug.
nothing to worry about
Oh ok thanks!
It’s a known bug where you’ve fed berries to a mon in a gym which is under attack. The attack animation then appears around you.