A Dugbog is a magical beast that dwells in marshes. Its most notable characteristic is its ability to remain perfectly still, at which point it is virtually indistinguishable from a piece of dead wood. This camouflage is its primary method of ambushing prey and defending itself. The Dugbog moves by slithering and gliding through its wetland habitat, propelled by its finned paws. It is a carnivorous creature, feeding primarily on small mammals. It is known to be aggressive towards humans who wander into its territory, often inflicting severe bites on their ankles and feet. The Dugbog has a particular fondness for the Mandrake plant, and Mandrake growers often find evidence of Dugbog attacks on their crop. (Fantastic Beasts and Where to Find Them)
The only appearance of a Dugbog in the original novels occurs during Harry Potter's Care of Magical Creatures Ordinary Wizarding Level (O.W.L.) practical examination. The exam, supervised by Professor Grubbly-Plank, required students to demonstrate a range of practical skills. One of the final tasks was to correctly identify a real Dugbog hidden among a dozen enchanted stumps. Harry Potter successfully identified the creature, earning him bonus points.