I'm developing a game and it burned itself into my display

During the development of my current game Tiny Thor (a beautiful 2D Retro Platformer, check out: http://asylumsquare.com/tinythor) I've implemented an invincible mode in our debug builds. To visualise it, I switched the rendering between normal and full bright with each frame - so a really fast flickering occurs on the players sprite when in invincible mode.

After using that feature for around 30 minutes on and off I suddenly noticed an inversed-looking Tiny Thor in the background of my text editor. I was very confused, so I moved the window around and discovered that the sprite was "burned" into my display over all applications, even after turning the display and the system on and off.

Here is a short video I took: https://youtu.be/oJHUqmtO6Gw

Seems like I have to do a softer effect on it if I don't want to destroy my display...

BTW: After turning the display off over night my lovely Tiny Thor vanished away. I'm missing him.... ;)