Xander and the Rainbow-Barfing Unicorns: Who Turned Off the Colors?

"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 color 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."
A paperback adventure book with an elementary to middle school reading level written by Matthew K. Manning & illustrated by Joey Ellis.