Surf's Up

A documentary crew follows the events of Cody Maverick, a 17-year-old rockhopper penguin who lives in Shiverpool, Antarctica with his mother Edna and his older brother Glen. Cody has wanted to be a professional surfer ever since a visit from legendary surfer Ezekiel "Big Z" Topanga several years ago. When a talent scout shorebird named Mikey (Mario Cantone) arrives to find entrants for the "Big Z Memorial" surfing contest, Cody jumps at the chance despite the lackluster support from his family. En route to the contest, Cody befriends another entrant, Chicken Joe.
The entrants arrive at Pen Gu Island, the site of the contest, where Cody meets and immediately falls in love with Lani, an eighteen-year-old female gentoo penguin who is a lifeguard. He also meets Tank "The Shredder" Evans, an egotistical penguin who has won the Big Z Memorial nine times since it was first held after Z's disappearance during a previous match ten years ago. Cody sees him disrespecting Big Z's memorial and immediately challenges Tank to a surfing duel. Tank easily wins the duel while Cody nearly drowns in an accident. Lani rescues him and takes him to her uncle, the "Geek", to help Cody recover from his injuries. Cody wakes up and panics when he can't find the souvenir necklace he got as a kid from Big Z. Geek downplays the necklace, but decides to return it when he later finds it in his hut.
While returning the necklace, Geek finds Cody sitting on an koa log and offers to help him make a perfect surfboard. They attempt to take the log back to Geek's house, only to lose control of it and end up on a beach far away from the contest. When Cody gets to the beach, he discovers a shack full of old trophies and surfboards, which are actually Z's belongings. After observing Geek solemnly reflecting in the shack, he realizes that Geek is actually Z and asks him to teach him how to surf. Reluctantly, Z agrees, but says that Cody has to make his own board first. The attempt doesn't go well, however, as an impatient Cody doesn't listen to Z's advice and makes a crude board that shatters as soon as he tries to enter the water. Frustrated, he storms off, running into Lani, who eventually persuades him to return. That night, a calmer, more patient Cody works on a new board, finishing it by morning, and falls asleep.
Z compliments Cody on his board, but when Cody is eager to start training, he instead has him do seemingly menial tasks unrelated to surfing. Losing his patience with Z, he places him on the board and pushes him into the water while he is asleep as a prank. Z asks him if he had fun, and when Cody tells "yes", Z takes him to the water and begins teaching him how to surf the waves, both being joined by Lani. Afterwards, Cody asks Z if he'll come watch the contest, but Z refuses, saying he faked his disappearance because he realized he couldn't compete with his then-new rival Tank, and that he was tired. Upset that Z just gave up, Cody angrily throws the necklace Z gave him to the sea and leaves, meets up with Joe, and gets back to the contest just as it begins.
Tank easily makes it to the finals, as do Cody and Joe. In the semifinals, Tank battles with Cody, with Tank playing with him, but he falls off the board and loses. During the finals, however, Tank bursts in and tries to knock Joe off his board. Cody intervenes at the last minute, sending him and Tank out of bounds and into a surfing obstacle known as the Boneyard, which has killed surfers who have ventured there. Tank knocks Cody off his board before crashing, and is rescued by Lani. Z, who had been secretly watching Cody's performance, rescues Cody from a gigantic wave and helps him get back to the beach.
Z and Cody find out that Joe won by default since Tank and Cody were disqualified. However, Cody accepts the loss, having decided he'd rather just have fun instead. Z reveals himself to the spectators and invites all of them to surf at his beach. Cody finishes his interview with a reflection of the past events and then joins the rest of his friends in the water.

Question: What does Cody panic about when he can't find it?
Answer: A necklace