Help Overlay??

[overlay 1]

Today when I was at the beach, I left my phone in my pocket, and when i pulled it out, i realized i've been pressing a lot of buttons. a few apps were open and for some reason there's this "overlay #1..." thing. It looks like a app/widget but it won't go away. It mirrors whatever is on my screen. I can enlarge/shrink it by dragging my fingers in and out but there isn't any options for me to get rid of it.
TLR there's this "overlay #1 1280x720 213 dpi " that won't go away.
My phone is a Samsung s4 active

 

[funkylogik]

Try long pressing the back button

 

[Alanb]

Try long pressing the back button

I have the same "Overlay" issue.
Holding the back button failed to fix it.
Help!

 

[funkylogik]

Have you maybe turned something on in developer options? Try turning dev options off to find out