"Bow Down / I Been On" is actually more like two songs, with the attention grabbing first half (where Queen B growls, "Bow down, bitches") produced by Hit Boy and Planet 6 and the second, arguably less-Beyoncé-ish "I Been Down," produced by Timbaland, Polow da Don, Sonny Digital and The-Dream.
The pitched-down section of the song allows Bey to get all #ratchet while rapping about smacking tricks and her dookie braids in a male-esque voice. It's not a new trend, exactly (recently, Mrs. Carter collaborator Azealia Banks did the same thing during an extended diss portion of "Van Vogue").
Now, thanks to the Internet and someone with Garage Band (or ProTools, if they're fancy) and a bit of time to kill, an unpitched version of the song has surfaced so that you can hear Beyoncé rap in her own voice.
The capital B means we're 'bout that life, so just consider us B! from now on.