My Gym Teacher is a Fairy — Duane L. Ostler

Blake Drywater's substitute gym teacher is a tiny, cute and cuddly fairy! Unlike other creatures from Mr. Marlin's world who waste no time trying to take him over and use his power, Blake's new fairy coach seems genuinely concerned about the welfare of his star pupil. The coach and his wife even share the special power fairies have over emotions to comfort Blake's family, and also show him the marvels of Fairy City where they live. But Blake has been fooled too often by other creatures to completely trust his new coach. He wastes no time in voicing his suspicions to his former science teacher, Mr. Marlin. But the annoying wizard is too busy setting up a new cookie business to listen! Meanwhile, Blake's friend Poindexter simply cannot believe a fairy could ever be dangerous. Only when it is too late does Blake discovers a startling truth about the fairies that even the wizards don't know-a truth that threatens to destroy him!