Matthew K. Manning 
Return to Pegasia [PDF ebook] 

Xander Stone travels to the home world of the Rainbow-Barfing Unicorns and it smells surprisingly good! Once banished for being stinky, zombielike, upchucking creatures, the Rainbow-Barfing Unicorns (still stinky, zombielike, upchucking creatures) return to their home world, Pegasia. Twelve-year-old Xander travels along, but Pegasia isn’t the wretched realm he expects. Instead, beautiful, brightly coloured, tra-la-la-ing unicorns roam this fairy tale-ish world. Heck, even their farts smell strawberry-sweet! Which is a problem, since the Rainbow-Barfers have just emptied their stomachs and are craving fruit-flavoured unicorns!