- "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 towards dinosaurs at first, Thunderclap is unforgiving towards dinosaurs who help his prey escape, with no qualms towards harming them afterwards. Despite being in a group, he does not consider the other pterodactyls as his friends 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 small fox 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 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 Ludodactylus.
- Real Nyctosaurus do not have teeth or wing claws like Thunderclap does.