Answer:
Once they sailed the sea, now they surf the web
This is needed both for courage and hardcover books.
I am the greatest teacher out of them all, but alas in the end I kill my pupils.
When the creeper passes, all the grass kneels
A precious stone, as clear as diamond. Seek it out whilst the sun's near the horizon. Though you can walk on water with its power, Try to keep it, and it'll vanish within an hour.
You use it between your head and your toes, the more it works the thinner it grows.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?