The 18th Emergency
"The 18th Emergency" is about a boy named Mouse whose penchant for labelling things lands him in big trouble with the school bully. After Mouse draws an arrow to the neandrathal on the school mural and writes Marv Hammerman, Marv wants to beat him up. Mouse and his friend Essie have devised plans for 17 emergencies, including what to do if they encounter an alligator or a python, but it's up to Mouse alone to figure out how to face the 18th emergency-- Marv Hammerman.
This book is kind of short on plot, but Byars' usual quirky details make it a fun read. The ending is a bit unexpected, and not all together satisfying, but it's still a cute book.