You had to do it big, but couldn't never stop the work
Now you heard my words and your bubble gonna burst
These two lines are directed at someone who also makes music, and doubted Mac’s ability to spit(most likely because Mac’s a pretty goofy white kid).
However, after this guy heard Mac rap, he was shocked, and Mac saying “your bubble’s gonna burst” means that guy won’t be so cocky anymore.
To help improve the meaning of these lyrics, visit “Whateva” by Mac Miller Lyrics and leave a comment on the lyrics box