- "The Pterodactyls are a search-and-rescue team of five. They like to sit back and let the often-treacherous storms in this part of the world do their dirty work, then reap the benefits of the devastation. But when these flying hunter-scavengers set their sights on Spot and Arlo, they’re in for a big surprise."
According to his introduction to Arlo, Thunderclap used to be frightful of the world around him. This changed when he was caught in a storm which no longer made him afraid. Following this, Thunderclap had a "relevation", realizing that the storm saved his life, therefore he must follow it. The experience made him obsessed with the storm's power, turning him into a sadistic scavenger as he relied more on the animals caught in the storm, gleefully devouring them every time. While he may come across as affable toward dinosaurs at first, Thunderclap is unforgiving toward dinosaurs who help his prey escape, with no qualms toward harming them afterward. Despite being in a group, he does not consider the other pterodactyls as his friends, despite that they all follow his lead, but rather fellow followers. This is also shown when he does not hesitate to fight his own scavengers over any meal found. Thunderclap is quite relentless and savage when it comes to prey that manages to escape, going as far as to pursue them until they are his to devour.
Like the other members of his flock, Thunderclap is a scavenger that follows storms to prey on trapped critters. He seems to be slightly deranged, having a sort of fascination and veneration for storms. He claims that he used to be scared and shy until he had a "relevation" when he saw "the Eye" of a storm. He believes that the storm freed him of fear. Thus, he renamed himself "Thunderclap", going by the motto that "the storm provides."
Following a violent storm, Arlo and Spot are found by the Pterosaur flock. At first, Thunderclap pretends to be friendly to Arlo; recounting to him his story. However, his true motives become apparent when he eats a raccoon whole that Arlo helped to free. Thunderclap and the others then set their sights on Spot. Arlo and Spot flee and are saved when two young T-Rexes named Nash and Ramsey come to the rescue and scare the pterosaurs away.
Sometime later, Arlo and Spot are stuck in yet another storm. Thunderclap and his gang find them again and they succeed at taking away Spot. With a newly-found courage, Arlo faces off the pterodactyls and defeats them. Thunderclap is about to eat Spot, but Arlo roars as loud as ever, making him turn in fear and giving Spot the chance to bite Thunderclap's left wing, leaving a gaping hole. As Thunderclap tries to fly away, Arlo grabs and throws a stick at him, causing him to fall into the river where he is carried helplessly downstream.
It is unknown what happens to him after this, but it can be presumed that he either drowns, washes ashore, weakens, or is unable to fly ever again. However, Peter Sohn confirmed on his Twitter that Thunderclap survived.
Thunderclap appears when the player stands on a pterodactyl's shadow in Journey Mode during later levels. Once the player stands on the shadow, Thunderclap will appear and land on the player and capture him or her, causing the player to lose a life or an instant game over, depending whether he or she is controlling Arlo and Spot individually or together. In Level 9 of Journey Mode, Thunderclap can be briefly seen capturing Spot in which Arlo must go save him from the pterodactyls.
Also whenever the player remains idle for too long throughout the game in Journey Mode or Endless Mode, Thunderclap will land on the player's character, causing him or her to lose a life or an instant game over.
- Thunderclap is the second villain from Pixar to be a pterosaur, the first being the Cleric in Toy Story That Time Forgot.
- The other four members of Thunderclap's gang are each a different species: Caulkicephalus, Guidraco, and two Ludodactylus.
- Real Nyctosaurus did not have teeth or wing claws like Thunderclap does, nor did they have feet strong enough for grasping.
- An action figure of Thunderclap produced by Tomy did portray him without teeth.
- Thunderclap currently has the shortest screen time of any Pixar villain.