In Harper Lee's To Kill a Mockingbird, Dill comes the first summer of the book to visit his Aunt Rachel. He is short for his age, though he is a year older than Scout.
Scout believes that under any other circumstances that Jem would never have looked twice at Dill. However, Dill has been to the movies and reads, and thus brings an entirely new wealth of ideas for them to role play when they "pretend."
He seems to have a limitless imagination...
When Dill arrives, he introduces himself and says he has seen the movie Dracula. Because Dill adds a new dimension to their playing (new roles, a third person—rather than two), Jem accepts him without question.
Dill had seen Dracula, a revelation that moved Jem to eye him with the beginning of respect.
Besides the fact that Dill likes to read and likes to play pretend, as do Jem and Scout, Dill is the mastermind behind deciding to get Boo Radley to come out of his house. The boys also are masters at developing the "Radley family" game, which entertains them for the entire summer. Dill is able to get under Jem's skin, though he is younger: for instance, it is Dill's dare (and the sense that the kids back at Dill's home are braver) that makes Jem decide to run into the Radley yard and touch their house.
Dill got him the third day, when he told Jem that folks in Meridian certainly weren't as afraid as the folks in Maycomb, that he'd never seen such scary folks as the ones in Maycomb.
Jem tries to work up his courage. Dill says that he and Scout will be right behind Jem to save him if it's necessary. With Dill's nagging and inferences of cowardice, Jem runs up and slaps the side of the house, running away as if his life depended on it.
Later in the novel...
Dill has declared he will one day marry [Scout], a statement she seems to accept matter-of-factly.
Dill quickly becomes like a member of the family; the three are seen together all summer long. Dill may seem young, and in some ways he is an innocent—as are Jem and Scout—but he has a wonderful imagination and is always coming up with new schemes that the adults may not like, but that Scout, and especially Jem, enjoy.
When sitting, Charles Baker Harris is not much "higher than the collards" in his Aunt Rachel's collard patch.
"I'm little but I'm old," he said.
The possessor of a head of "snow white hair," Dill quickly becomes known for his wild imagination and for the movies that he seen (Maycomb has no movie theatre), especially Dracula. According to Dill, who soon becomes known for his "whoppers," he won a beauty pageant in his home of Meridian, Mississippi, and went to the movies 20 times on the $5 first prize. Scout referred to him as
... a pocket Merlin, whose head teemed with eccentric plans, strange longings, and quaint fancies.
His primary interest quickly turns to Boo Radley, and the idea of Boo sticks with him for an entire year. Upon his return to Maycomb the next summer, Dill brags about seeing Siamese twins and claims his father is "president of the L&N Railroad" and his grandfather is Confederate cavalry legend General Joe Wheeler. He invents the Boo Radley Game that the children perform on the sidewalk in front of the Finch house, and Scout grows to admire his acting skills.
Dill was a villain's villain... He was as good as his worst performance.