The Magical Grass

Once there was a boy named Theo who was skipping along some magical grass. As he stumbled across the icy grass, he saw a mysterious key.  He picked it up and when he held it, he was sucked up to a shed 25 feet long and 20 feet wide. He opened it up. Then he saw 10 more doors in front of him.  Suddenly, the gate shut behind him. He peeked through every door but every time he opened and closed them, what was inside would change until he fell to the floor in confusion.  Later he woke up at the same grass. He ran off the grass and never turned back.