One of the many denizens of Exclamation Point on the Isle of Wonder, the Bookworm takes care of and lives in the multitude of books all while watching over the strange word beasts, such as Oxymoron and Dipthong, that reside there. When travel between the islands became difficult and dangerous, he warned the adventurous Dangling Participle not to leave the Isle of Wonder. This did not prevent the creature from wandering off soon after, and disappearing.
The Bookworm encountered Alexander while the prince was seeking a rare book, and he was quite mortified when the human told him that he hadn't realized the books there were owned. Despite this, the Bookworm was willing to trade a rare book for an equally rare item. At first Alexander offered his incomplete sentence, which the Bookworm refused. Later, Alexander returned with the worm's missing charge -- Dangling Participle. Pleased to see the disobedient word beast again, the Bookworm produced a riddle book for Alexander.