* Is a misheard or misspelled word: There might be a similar phrase or word you're trying to recall.
* Is a slang term or regional expression: It could be a term used in a specific community or region, but it's not widely known.
* Is a fictional term: Perhaps it's from a book, movie, or TV show.
To help me understand what you're looking for, could you provide more context?
For example:
* Where did you hear this phrase?
* What was the situation?
* What language do you think it might be from?
With more information, I might be able to help you figure out the meaning of "rula bula."