Answer:
What five-letter word becomes shorter when you add two more letters?
My first is twice in apple but not once in tart. My second is in liver but not in heart. My third is in giant and also in ghost. Whole I’m best when I am roast.
A leathery snake, with a stinging bite. I'll stay coiled up, unless I must fight.
Scythe of darkness, Shadow’s light. Guiding eye of thirteenth sight.
Useful tool for who in darkness dwell. Within you, corrupting like a deadly spell.
It can be cracked, It can be made, It can be told, it can be played. What is it?