Derek Thompson is the main protagonist from the 2010 comedy Tooth Fairy.
When Derek discourages a youngster's hopes, he's sentenced to one week's hard labor as a real tooth fairy, complete with the requisite tutu, wings and magic wand. At first, Derek "can't handle the tooth" - bumbling and stumbling as he tries to furtively wing his way through strangers' homes...doing what tooth fairies do. But as Derek slowly adapts to his new position, he begins to rediscover his own forgotten dreams.
Derek Thompson is a minor league hockey player nicknamed the "Tooth Fairy" for hitting opposing players so hard that he knocks out their teeth. One night, Derek steals a dollar from his girlfriend Carly's six-year-old daughter Tess that had been left for her lost tooth and tells her that the tooth fairy doesn't exist. Then he receives a magical summons under his pillow. He grows wings and is transported to the realm of tooth fairies. He meets his case worker, Tracy (Stephen Merchant) and the head fairy, Lily (Julie Andrews). He has an adversarial relationship with them. Lily tells Derek that he is a "dream crusher," due to his unsympathetic dealings with children like Tess. He is sentenced to serve two weeks as a tooth fairy. Later, he meets Jerry who gives him his tooth fairy supplies, which include "Shrinking Paste," "Invisible Spray," and Amnesia Dust."
Carly's teenage son, Randy dislikes Derek. Randy wants to grow up to be a heavy metal star. When Derek defends Randy against a bully, he begins to win him over, and Derek begins teaching him to play his electric guitar better so he can win a talent show.
Derek visits several children and tries his best to be a good tooth fairy, but ends up causing more harm than good. Lily says that he is the worst tooth fairy ever and denies him more supplies for the remainder of his sentence. He buys black market supplies from another fairy named Ziggy, but they malfunction and he is seen by a child's mother and arrested. While behind bars, Tracy tells Derek that his duty is extended to three weeks. Carly bails Derek out.
Despite managing to improve his tooth fairy skills, as well as bonding with Tracy and continuing to bond with Randy, this progress is halted when Derek becomes frustrated after he can't score a goal at a hockey game. He takes his anger out on Randy, telling him that he will never become a rock star. His dreams crushed, Randy smashes his guitar and Carly breaks up with Derek. Later, Tracy comes to Derek's house and announces that he is a tooth fairy in training, but that Derek's cruel remarks hurt himself more than others. The next game, Derek gets back on the ice and sees Tracy. Tracy wants to teach Derek the importance of dreams, encouraging Derek to score a goal and to go get Tess' tooth. With a renewed spirit, Derek scores the goal, gets into his tooth fairy costume, and flies away while Tracy spreads Amnesia Dust on the audience to cover up the event.
At Carly's, Tess sees Derek taking her tooth, but she promises to keep it a secret, and Derek apologizes to Randy and encourages him to keep pursuing his dreams, using his magic wand to grant Randy a new guitar. Downstairs, Carly sees him as a tooth fairy, but assumes that he rented a costume for Tess' sake, causing her to forgive him. Derek flies Randy to the talent show and throws Amnesia Dust on him when they arrive.
Derek heads back to the fairy realm to give Lily the tooth, and is told that because of this job, as well as reaffirming Tess' belief, he has been relieved of his fairy duties. Lily explains that he will never see the tooth fairies again and he will have Amnesia Dust thrown on him. Before departing, Derek says a friendly goodbye to Tracy. Lily throws Amnesia Dust on Derek and transports him back to the talent show. There, Randy outperforms everyone and ends up forming a band. Derek proposes to Carly, and she accepts.
During the credits, Derek is shown playing left wing for the Los Angeles Kings, and when he sees Jerry in the crowd, he doesn't recognize him. His fairy friends secretly help him score a goal.