Mr. Popo..
..is by far the weirdest thing on Dragon Ball Earth.
What is he, anyways? There's nothing quite like him on the planet, or anywhere else.. Kami, Dende, and Piccolo are aliens. Talking animals are fairly common place. Buu, he's a magical being, and demons and other weirdo's are from hfil/otherworld.
If I didn't know better, I'd almost think Popo was Toriyama playing a "blackface" stereotype, but maybe there's a cultural reference I'm missing?