What is That Comment Everyone is Talking About on Fantastic Baby?

So, I went to re-listen to fantastic baby for the millionth time, and I began to scroll through the MV's comments when I noticed everyone was mentioning something about finding a certain comment. From reading other comments I picked up that a new Kpop fan (?) who only knew BTS said something along the lines of: "Big Bang is copying BTS." I tried to Google it and nothing seems to come up, where did everyone find this information from? I am genuinely confused.
Oreoyumyum304
2 weeks ago
@-sputnik- Thanks
-sputnik-
2 weeks ago
http://imgur.com/a/7Q8Frxn
-sputnik-
2 weeks ago
It's this