Beast Quest: Nixa the Death Bringer by Adam Blade

The air vibrated with a sound like thunder. As the farmer stared in horror, the woman began to change. Her arms split and became a mass of thrashing tentacles. Her two eyes divided into a cluster of bulging, glistening spheres. Her scarlet robes dissolved and her body sagged into a thousand wrinkles. Green slime seeped out from her and dripped onto the ground.