In a medium saucepan, bring the water to a boil. Stir in the oats and Yondu; simmer over a low heat until thick and creamy, about 8 minutes. Remove from the heat and set aside.
Meanwhile, heat the oil in large skillet over high heat and add the mushrooms and Yondu. Sauté until browned, about 3 minutes. Stir into the oats.
To serve, simply add the mushrooms to the oats.