I assume that it also doesn't charge, and that changing colours on the display is a secondary effect?
Have a look at your charging port, and make sure there's nothing stuck in there (bit of dirt etc). If there is, be careful cleaning it - try not to use anything too hard that might damage the pins.
"Gear VR" is basically a Samsung VR headset that uses the phone as a display device. I assume it's supposed to be activated by attaching the phone to the headset (I've never seen one in reality, so not certain), which is why my first suspicion is that there's a bad connection which is fooling the phone into thinking it's been connected to the Gear VR headset rather than a charger.
A bad cable is another possibility - have you tried using a different cable to charge it?
The worst case could be that the charging port is damaged, but hopefully it's not that.
