Most painfull move in mk9 that would hurt the most in reallife!

JC's nut buster most definitely, Mileena's face chew, and Ermac's Tele-Slams, to name a few.
 
Goro's X-ray move, Ermac's X-ray, JC's X-ray, Kano's X-ray...practically every single x-ray!

Noob's Fatality, Ermac's fatality, Kano's Fatality, Ermac's tele slam, Snoya's leg grab, getting hit by all of Baraka's moves that include his blade, being close to Jax's aura of total grabbing massacre O-o

Etc.
 
If were talking about just moves, then Reptiles ACID spit to the face rises above all other moves! come on guys, that melts your face off! PAINFUL!!!! a nut punches pain passes!
 
Probably Jaw's MKII Arm Rip. It would be physically painful to go through, but you'd probably survive but you'd have no arms, which would mean no video games... among other "activities".
 
Kung Lao's buzzsaw fatality. You have to experience the horrificness of having your body cut in half vertically.... Starting with your crotch.
 
All of them will be painful, but ones that come to mind are johnnys ball breaker, reptiles acid spit, scorpions spear, sektors xray, noobs fatality and xray, the taxi cab fatality, the melt your face off in lava fatality, and mileenas fatality (cuz your still alive for 15 seconds after your head is tooken off)
 
Top