"Mwahahaha!" the human twirled his mustache. "I am immune to magic, which means that a mere unicorn like you is powerless before me!"
"Physics bubble, right?" Twilight prompted.
"Yeah," the human grumped. "You could at least pretend to be surprised."
"And," Twilight continued her train of thought, "I suppose that not only our light, but also our gravity must be compatible with your physics? After all, the ground seems to be holding you down fairly well."
"Yeah, why do you-"
*thunk*
"Help, I've fallen and I can't get up!"
Not quite sure what she's done here, but it occurs to me that in addition to his magic immunity he's got a truly astounding recuperative ability going for him.
10342740
Gravity intensification spell?
10342760
i was going to say manipulation
but yours seems to be more accurate