Dylan Piper is one of the main protagonists of the series Halloweentown. He is the middle child and only son of Gwen and William Piper, grandson of Aggie, younger brother of Marnie, and older brother of Sophie.
Dylan is somewhat of a book nerd as he likes to study more than anything. He strongly dislikes Halloween and everything that goes with magic. Dylan is sarcastic and frequently teases his sisters, especially Marnie. He is the only warlock in the family, but doesn't like to use magic but will use it sparingly to help his family. In the film Halloweentown he demonstrates meteromancy.
Marnie and her mother, Gwen arguing over why she and her younger siblings Dylan & Sophie can never go out for Halloween, and why Marnie cannot go to a costume party. Her mom offers no clear explanation. Gwen's mother Aggie, who is an expert witch, shows up for her annual Halloween visit. The children are happier to see Aggie than Gwen is, as Aggie openly encourages the children to get more involved in Halloween.
Before heading home, Aggie reads the children a bedtime story called "Halloweentown", a mystical place where witches, vampires and monsters of all sorts live in peace. Sophie points out a drawing of a witch in the book that resembles Marnie; Aggie does nothing to stop Marnie from imagining such a thing.
When Aggie leaves to return home, Marnie and Dylan follow her. They see Aggie getting onto a magical bus, and sneak onto it through the back door. When they arrive in Halloweentown, Aggie does not see Marnie and Dylan getting off the bus, and the children lose sight of her. At the same time, Marnie and Dylan realize Sophie snuck onto the bus. They begin looking for Aggie, and are approached by Kalabar, the Mayor of Halloweentown. He whistles for a cab which is driven by Benny, a skeleton with a bad sense of humor. The children find their grandmother's home, and against her better judgment, Aggie decides not to take them home immediately. She says she will start Marnie's witch training, but has to take care of "the bad thing" first. She shows her grandchildren what she is talking about: in her cauldron, a vision of a hooded demon appears, laughing maniacally. She says she must activate Merlin's talisman with a spell and potion to defeat the demon.
In town, the family is introduced to Luke, a goblin who was made handsome by a shadow demon. He makes a clumsy pass at Marnie, which she turns down on the spot. Gwen arrives in Halloweentown with plans to bring her children home, much to Marnie's objections. Gwen cannot find another bus back to the mortal world and decides to see if the mayor can do anything to help. She is shocked to see that the mayor is Kalabar, an ex-boyfriend of hers. Kalabar briefly leaves to handle another problem, Gwen and her children see Aggie walking somewhere with Luke. Sensing Aggie might be in trouble, they follow Aggie and Luke to an abandoned movie theater.
Gwen and the children enter the theater as Luke rushes out in fear. The demon freezes Gwen and Aggie. The children escape, and obtain the necessary ingredients–the hair of a werewolf, the sweat of a ghost, and a vampire's fang–to make the talisman regain its power. They then realize they must install the talisman in the large jack-o'-lantern in the center of the town.
When they arrive to install it, the demon suddenly appears and reveals himself to be Kalabar. He starts talking to the townspeople and tries to persuade them to join him and take over the mortal world. With the help of Luke, Marnie slips past Kalabar long enough to climb up onto the jack-o'-lantern and try to place the talisman inside. Kalabar, noticing her, freezes her. As she is about to pass out, Marnie drops the talisman inside the jack-o'-lantern, which causes it to illuminate. This unfreezes herself and everyone trapped inside the theater, as well as severely weakens Kalabar. Gwen, Aggie, and the children confront Kalabar and use their combined powers to defeat him. The film ends with the family getting on the bus and blasting off to the mortal world.
Halloweentown II: Kalabar's Revenge
Aggie contacts her grandson Dylan back home for a spell from her spell book. Dylan and Sophie discover the book is missing.
Sophie and Dylan realize that Alex, believed to be Kal's father, is actually a golem intended to distract their mother Gwen at a high school Halloween party. Kal puts his spell into effect, turning the party guests into the monsters they are dressed as, resulting in chaos. Dylan and Sophie hide from the monster humans including their mother.
Marnie contacts her siblings and they create a new spell that forces the portal between Halloweentown and the mortal world to reopen permanently. Kal angrily confronts Marnie, who mocks him and demands the spell book. Kal produces slimy living serpent vines of dark magic and uses them to take both spell books in an attempt to prove his own superiority, which fails when Marnie takes them from him. Kal is sent away by the vines and the family breaks his spells in the mortal world and in Halloweentown.
Two years after the previous movie, Dylan prepares to begin a new school year.
Return to Halloweentown
Dylan is reluctantly forced along by Gwen to keep an eye on her. The school is not what it seems, as witches and warlocks cannot use magic; instead they learn about Shakespeare and old magic history.
Sinister Sisters, a triad of malevolent, extremely snobby, spoiled, and manipulative witches with whom Dylan is immediately infatuated and are the daughters of Silas Sinister.
Marnie and Dylan learn that the box contains the Gift, a magical power only a Cromwell can use, which Splendora locked in the box centuries ago. Meanwhile, the Sinister sisters use Dylan's infatuation with them to make him do their homework and use as bait for Marnie.
Sinister Sisters transform Dylan into a dog to compel Marnie to comply with their demands. If Dylan is not turned back, he will stay that way forever after Halloween passes. They agree to return him to his natural form if Marnie controls Halloweentown for them. Marnie falsely agrees to aid them in their plot, but turns on them once Dylan is returned to normal. Marnie, Dylan, Gwen, and Aneesa destroy the Gift. The Dominion attempt an escape, but are apprehended by Periwinkle who is revealed to be an undercover detective of the Halloweentown Anti-Dominion League. She imprisons them in a Witch's Glass where she has stripped them of their magic and arrested them for treason.
The movie ends when Dylan discovers that Marnie did not destroy the Gift, but instead left it for him in a book. Since spells cast on the grounds of Witch University become permanent at midnight, the Gift belongs to him, the only person Marnie trusts with its power. Saving the power of the Gift for important uses only, he puts the book back showing a glowing red S at the end of the film.
In Halloweentown, he is 12 years old.
In Halloweentown II: Kalabar's Revenge, he is 14 years old.