I'm skinny and long with a wooden coat, I write down words and math you note. I leave dark marks that you can erase, what am I, helping in every case?

If you come to the sea you'll have a whale of a time, Expensive by boat; on shore won't cost a dime, You'll hear me breathe as my fin breaks the surface, I may look like a shark, I swear we don't do it on porpoise!

Come on third I will there to great thee, Of course after gold and silver shine above me.

OSHA would hate my work conditions, full of lava pits and turtle collisions.

I have four legs but cannot walk, and a flat back but no spine. I gather families for dinner, but I never eat nor bite.