S1, E5: Jake notices that the curtains of the surprise area are twitching, and he and the other Tweenies decide there is a monster behind them. To their horror Judy pulls a book from behind the curtains, but she doesn't seem to have seen anything scary. When the story about Mr Underbed is finished they admit they are scared of what might be there. Judy encourages them to have a look. When they do they are glad they did.