Answer:
I am the place to turn to when nature calls. What am I?
Cold head and feet; round as a ball; always turning around myself.
A single syllable do I claim black was my most famous name; Fetal to mortals here below thousands have I slain in a single blow.
I can be entertaining until you realize some pieces have been lost.
Two in a whole and four in a pair. Six in a trio you see. Eight's a quartet but what you must get is the name that fits just one of me.
What language does a billboard speak?