Why are your eyes so big?
There is a German fairy tale (“Rotkäppchen”, I think its “Little red riding hood” in English) where this sentence is rather central.
Outside of this context, it does not make much sense:
… Per guardarti meglio. Perché i tuoi denti sono così grande? Per mangiarti/divorarti meglio! … (please correct)
Is the fairy tale also popular in Italy or is it a coincidence?