Of course Arya had candy on her person, it was one of the items she always carried around, just in case she got the munchies. Heh. That didn't mean she wanted to give it up to the creature.

And she was sort of fascinated by the thing, couldn't it stay a bit longer?

With her left hand she dug into her pockets, pulling out ONE piece of gum and tossing it with the others to the forest. Then she moved over beside the other prefects and held her wand at the ready should the have to use them. And don't think Arya wasn't already curious as to how the professor was going to protect them from the creature without having his wand out.

He DID have it.... somewhere, right?