Twilight screamed.
She screamed some more.
...and some more...
...and some more.
The mare continued her wailing throughout the day, throughout the night, for days on end. She didn't eat, sleep, nor drink, for she was immortal, and such lowly activities were unneeded.
She continued to scream, and by the second week, word of her frighteningly large lung capacity had spread throughout Equestria. Soon enough, the mare had grown an absurdly large gathering of followers, of whom donned large wigs of cheese, and belted out to their hearts' desires in the hoofsteps of their new god.
Celestia chuckled as she watched from her balcony, for she had created a religion by simply dumping a bucket of melted cheese on her former student as she slept.