Answer:
This small creature kills even the largest one.
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 toast.
For our ambrosia we were blessed, By Jupiter, with a sting of death. Though our might, to some is jest, We have quelled the dragon's breath. Who are we?
To you, rude would I never be, Though I flag my tongue for all to see.
What always goes to bed with its shoes on?
What sphinxes employ and players enjoy.