Weird Charging Graphic on Login Screen

[GSWForever8]

Today when I was logging in onto my Mac, I noticed a weird charging graphic appear. It only appeared for a second before disappearing. Can someone explain how this happened and the keyboard command to get this?(This isn't mines, but it's about the same image as what I got.

 

[tensixturtle]

As far as I know, I think it appears in the login screen when the computer is sleeping and then you plug it in. Unfortunately, I think it cannot be activated permanently, similar to the charging icon on the iOS/iPadOS lock screen.