What’s your favorite costume for Halloween? The five little monkeys chose a banana, an alien, a ghost, a goblin and a princess for their costumes in Five Little Monkeys Trick-or Treat, by Eileen Christelow. Their babysitter, Lulu, is taking the five little monkeys out for trick-or-treating. They meet lots of friends, all in different costumes. What costumes will the five little monkeys end up wearing by the time they get back home?