Dan was always the type to make the situation seem worse than it actually was, or maybe perhaps even exaggerate what he was seeing. So when they first heard his words they thought it couldn't be true. After all, no one had heard or seen a dragon for the last 100 years.
Many people had even predicted that Dragons might have never existed in the first place. They were just a powerful beast that people exaggerated about.
So as soon as they heard Dan's words, of course, they didn't believe him. But when they all looked up, they could indeed see a giant creature in the air. It had wings, a tail, and a long head, all the traits of a dragon.
"I thought they had all gone extinct?" Slyvia said.
"I don't think that's the problem right now" Monk replied, "how are we meant to deal with a dragon and the Slime snakes?"