It wasn't as if he meant it, it just slipped! He would never, EVER, call Lily a Mudblood.
'But you did, Snape. You did and you lost her.' said a small voice in his mind, making him dig his fingers on his skull and pull on his raven hair.
Severus Snape dragged his feet towards the Hogwarts Grounds, away from Potter and his minions. The boy sighed deeply, glancing up at the moon, deep in thought.
Just then, small bright lights glowed by the trees, illuminating it's leaves and trunks.
The fireflies gave light to them.
Just like how Lily gave light to his.
But the light's dimming, fading away..
"Lily, don't go."