I bet that gave you a fright !
Possibly just a glitch @Quartzer but if it happens again there are troubleshooting tips you can use such as Safe Mode and or a Samsung Experience Store or Samsung Service Centre can take a look.
Daily Driver > Samsung Galaxy s²⁴ Ultra 512Gb ~ Titanium Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "
