I don't know, it's not quite mystical, but I'd quite like to go and visit other planets. That would be quite fun, "Oh I fancy going to Jupiter. Oh dear, it's a bit bubbly down there, I'd get my fingers burnt, but..."
There's all sorts you could do, the old classic one is mind-reading I suppose. Invisibility is a bit boring, because it doesn't give you any special powers, you're just hidden. Although you could... yes, my male fantasies are going wild here, so we shall stop that right there.
"There are things in this world that do not belong here - evil things. Supernatural creatures that are neither myth nor legend. They are, in fact, quite real."