Giygas, because pressing an "attack" button is not nearly as threatening as sword to sword combat with an creepy looking epic demon thing who can summon lightning and shoot it at you whenever he wants.
Elephant. Also, I think he met if they were real. I don't think you'd want to be in the same room as this.
Anyway, WYR Have Gyiyg be real and have to fight him (His second form, as shown in the link above.) or have Majora and the Moon be real and have to save Termina, and then fight Majora? The Mask transformations are really painful...
WYR only listen to your favorite song for the rest of your life or listen to all other songs except for your favorite for the rest of your life? (idk I suck at these)