Are you kidding? The most powerful spell ever is preformed every single day!
Barring the truly righteous acts of deities and their solar manipulating phenomenon, I saw Twilight Sparkle against that Ursa Minor. Those were just some epic spells she displayed, but some epic brainpower too.
She not only lifted a water tower filled with milk, but an entire Ursa Minor too, at the same time! And then she carried them both all the way back to its cave! That’s about as hardcore as I think it can get.