First connect to secondary display and see if you get a picture there and if your GPU is recognized. Because if your GPU was cooked it should not show up in device manager and if it doesn't show then your PC will use intel HD graphics and those won't glitch because then your CPU would be damaged as well and you wouldn't even be able to get here.
I suspect its the cable that got destroyed or the connection on the motherboard.
Asus Rog G750JZ
Screen: 1920x1080 17.3'
CPU: Intel® Core™ i7-4700HQ (3.4Ghz @ -70mV)
GPU: GeForce GTX 880M 4GB (OC +125Mhz Core, +600Mhz Memory @ 1.062V)
RAM: Samsung 32GB 1600MHz
Storage #1: Samsung Evo 840 250GB
Storage #2: Samsung Evo 850 500GB
Storage #3: Seagate Barracuda 2TB
Storage #4: Samsung Evo 128GB MicroSD