Justina Ireland 
Zach Lopez vs the Unicorns of Doom [PDF ebook] 

Zach Lopez has just moved to Devil’s Pass and is missing his old home already. When he meets Tiffany, Jeff and Evie in his new school, they tell him the town isn’t what it seems and that strange things happen there. Zach doesn’t believe it until he sees a glimpse of a white horse with a horn and a mane full of glitter. Could it really be a unicorn? Soon, Zach finds that his new friends were telling him the truth and more, that they have to save the town from a brutal infestation of carnivorous unicorns before the whole town gets eaten.