GFCI? what is it? is it a must? how do i install?

Im ordering a 250 watt hps very soon
starting construction on the secret garden(2dx3wx8t) in the closet tomorrow

i read about this GFCI outlet thing for the hps lights in the scrog bible, this is my intentions
and i figured if thats what is recommended then i should look into it

riu is the best forum so ill ask yall
is it needed? if so how do i install it
mother-in-law is petrified of any house modification even if it is a hole in the sheet rock in the closet for air ventilation (who cares if the house will burn down without it or the fact that im wasting space and money and all this other shit noone else cares to learn about)
she is just, anyways it drives me nuts
i know i can do anything if i have access to the internet, anyone can so dont put the you cant do it past me
i will learn how

wow i shouldnt get stoned and ramble
anyways about the gfci any info would be greatly appreciated

A GFI is just an outlet with it's own breaker in it. Any disruption in current (AKA water contact - this is why they are mandatory in every building for any outlet within 5 ft. of a water source.) and it trips the breaker. Just a safety precaution and will not matter at all in concern of the house. Good luck bro!