One Big Frog is a episode of Dinosaur Train season 3.
The Pteranodon kids are playing a game called “I’m the Biggest,” which raises the question: how big is the biggest frog? Dad takes the kids on the Dinosaur Train to find the biggest frog ever, the legendary Beelzebufo. Once off the train, they have to take a river raft to find this illusive creature, but find him they do. The kids are surprised to find that Benny Beelzebufo isn’t nearly as large (or mean) as they’d imagined, but he is definitely the biggest frog they’ve ever seen! Benny teaches the kids about his “sit-still-and-wait” hunting style and shows off his large, floating leaf “home.”