Matthew K. Manning 
Who Turned Off the Colours? [PDF ebook] 

The Rainbow-Barfing Unicorn virus hasn’t infected humans … until now! In this adventure, twelve-year-old Xander contracts the mysterious virus of the Rainbow-Barfing Unicorns. The virus gives the unicorns their barfing abilities, but it’s having the opposite effect on Xander, it’s draining him of any colour at all! Xander’s fate lies in the hands er, hooves of Ronk, the most dimwitted of all Rainbow-Barfing Unicorns. This is not good. In fact, this is bad, really, really bad. Plump-full of grotesquely delightful characters and fantastical realms, Xander and the Rainbow-Barfing Unicorns from writer Matthew K. Manning (Batman/Teenage Mutant Ninja Turtles Adventures) is so epic it’ll make you wanna puke.