Ari Davis, an athletic gymnast, is going to Camp Full Moon. On the bus ride to camp, he befriends Dustin Minium. Ari loves practical jokes; he suggests that he and Dustin trade names at camp as a prank.
When the boys arrive at camp, Dustin (pretending to be Ari) gets put in the best bunk, and Ari (pretending to be Dustin) gets put in the worst bunk. That night, Ari wants to switch back, but Dustin says he wants to keep up the act.
When Dustin finds out that "Ari" has been volunteered to face off against The Snatcher, a deadly creature that lives in the woods, he tries to trade places back with Ari, but Ari refuses to reveal his true identity.
Ari goes through great lengths to avoid having his true identity revealed. When Logan, Dustin's younger brother, arrives at camp, Ari talks to him. Ari threatens to hurt Logan if he reveals Dustin's true identity.
Ari loves knock-knock jokes and pranks. Early on, Ari seems like a well-composed and friendly person. However, Ari becomes nasty when Dustin's brother, Logan, arrives. Ari threatens to hurt eight-year-old Logan if he tells anyone that they aren't related. Rather than facing The Snatcher himself, Ari forces Dustin to go in his place.
Ari has brown hair and green eyes. His face is covered with freckles. Ari is incredibly muscular. He first appears wearing a black t-shirt and a black, backwards baseball cap.