Answer:
What has two spines and a lot of ribs, and carries much but never moves?
Don't do this in the shallow end.
You will find me with four legs, but no hair. People ride me for hours, but I don't go anywhere without needing to be tugged. Jerked or turned on, I always manage to be ready for work.
If all Wibbles are Criggles, all Borkins are Kwumblins, no Hoggles are Borkins, and all Criggles are Borkins, is it true that all Borkins are Criggles?
What has two legs but doesn't walk?
When is it bad luck to see a black cat?