Jethro and the Jumbie
Susan Cooper
Angry at his brother for not taking him deep-sea fishing, Jethro stomps off, meets a jumbie, and enlists its help in changing his brother's mind.

by Nick Ward (2005)
When their parents leave baby sharks, Sammy and Sophie with a babysitter, things are so exciting Sammy has to work hard on his unfortunate "biting" habit.
Susan Cooper
Angry at his brother for not taking him deep-sea fishing, Jethro stomps off, meets a jumbie, and enlists its help in changing his brother's mind.