Answer:
They are toothy nocturnal immortals.
It comes from crystal and melts to a treat. Add it to your tea to make it sweet. What is it?
Without this, H2O would just be 2O
An artΒ-form and its colour-ful result.
The more you look at it, The less you see.
Walk on the living, they don't even mumble. Walk on the dead, they mutter and grumble.