Retardation light

A term used only by the craziest people of the internet when they're losing arguments. Used to indicate that their opponent is supposedly so retarded that they cause others to lose braincells by just being nearby.

Twitter post: 2+5-3*0+6*2 = what? USE YOUR BRAIN NOT A CALCULATOR
Math nerd: 19.
Nutter: Its 12.
Math nerd: No, it's 19 because of PEMDAS.
Nutter: Anything times zero equals zero.
Math nerd: Multiplication is solved first. 3 is multiplied by 0 before it can be subtracted from 2+5.
Nutter: Sure keep shining your retardation light.