If you keep doing that, then... (negative outcome): 그러다가

This pattern combines 그러다 (from 그리하다 meaning ‘to do that’) with the [하 ]다가 structure (to V1 and then V2). It is used to say “If you keep doing that then X will happen”, where X is often a negative result:

그러다가 게을러지겠어요.

If you keep on like that you’ll become lazy.

그러다가 살이 찌면 어떻게 해요.

If you keep on losing weight like that, what will happen to you?!

그러다가 물건을 깨뜨릴 거예요.

If you keep doing that you’re going to break something.

그러다가 친구가 없면 어떻게 할 거예요?

If you keep doing that you’ll have no friends and what will you do then?

그러다가 뭐?!

And then what, huh?!

그러다가 돼지가 될 거예요.

If you keep on like that (overeating), you’ll turn into a pig.

그러다가 돈이 떨어지면 어떻게 할 거예요?!

If you keep on like that and you end up broke, what will you do then?!