What does the Cyclops do that puts Odysseus and his men in danger?

I'd say the obvious thing is that Polyphemus trapped Odysseus and his men in his cave and threatened to eat them. Other than that Odysseus' cleverness protects them fromanything else Polyphemus tries to do. He was rash when he shouted out his real name to the cyclops though as Polyphemus' father is Poseidon and he calls upon him to avenge his blindness.