Realizing that everyone already mentioned the Giant Squid, grindylows, and plants no one cared of, the third year tried thinking of something else. So what creatures live there?, Gwen asked herself and remained silent for a moment. Suddenly, she remembered reading somewhere stuff about the period when Harry Potter was at Hogwarts. Something with Neville's toad escaping in the lake... That's it! 'There are some toads too', the Ravenclaw said. If I don't even get this one, then I am a troll. For sure.