Wood lice are crustaceans that live in trees. In appearance, they somewhat resemble grains of brown rice. They are a favourite food of Bowtruckles, and are offered to them by wizards and witches who wish to obtain wood from the tree they live in to use in making wands. Wood lice can also be used as potion ingredients. In 1995, Professor Grubbly-Plank scattered some of these to placate some Bowtruckles as she taught Rubeus Hagrid's fifth year Care of Magical Creatures about them.