Mulgarath is a fictional character from the Beyond the Spiderwick Chronicles series, created by Tony DiTerlizzi and Holly Black. He is depicted as a powerful and malevolent creature, often described as a shape-shifter with a cunning and manipulative nature. Mulgarath seeks to obtain the Spiderwick Field Guide to gain control over the magical creatures and realms it describes. In the story, Mulgarath serves as the primary antagonist, posing a significant threat to the protagonists, the Grace children. His desire for power drives the plot, as he attempts to thwart the children's efforts to protect the magical world. Mulgarath's character embodies themes of greed and the consequences of seeking dominion over others.