I made that up. (다 내가 꾸며낸 거야. )
(=I created all of that stuff, It was all just a fabrication, I lied.)
A: So, you're uncle is the president of Samsung?
B: No, I made that up.
A: Oh, but you own Samsung stock, right?
B: Nope. I made that up, too.
A: Did you make up all that stuff about Samsung?
B: No, I do have a Samsung cell phone.