럴수 럴수 is meaningless interjection transformed from 이럴수 used for comical emphasis Only 이럴 수가 means "OMG" 이럴 수가 is a short form of "어떻게 이럴 수가 있어!" How can it be like this! 이럴 수 << 이렇(다) + ㄹ + 수 이렇다 : be like this ㄹ : modifier suffix for assumption or future tense. 수 : method, way, possiblity 이럴 수가 있다 : it can be like this, A/V+ㄹ 수(가) 있다 : be able to V, can be A e.g 먹을 수가 있다. It is edible

In addition, I think this is some kind of transformed form of "oh my god" such as (just example) "oh my oh my ooh my goooood" This is just a punning, and im not sure but this was a buzz word