Answer:
I sit in a corner while travelling around the world.
When you are inside me you will be encouraged to slam other cars.
The more you work the more I'll eat.You keep me full I'll keep you neat.
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 have a mouth on my head and eat everything.
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.