What is that hip-hop/rap/breakdancing song with the low br instrument playing the same eighteen notes over?

I know it's a total stab in the dark asking this over the internet but it's a song with a low-sounding br instrument playing a b line like "ba-ba-ba-ba-ba baa baa baa, ba-ba-ba-ba-ba baa baa baa" and it carries on repeating. The second bar is a repeat of the first in a lower key, and the two bars keep repeating. It's a famous song