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In season 1, episode 4, "Blue's Story Time," the second clue is a wolf. The toy wolf with the pawprint on it could be frightening to younger viewers. Same goes for the Steve drew it in his notebook and the music that plays along with it during Thinking Time. The toy wolf moves to act out his parts in "The Three Little Pigs," which is what Steve reads, as it was the answer to Blue's Clues. The last scene with the toy wolf could be VERY frightening.