What type of creature is Dobby?

The story behind the answer

Dobby is a house-elf, first seen in Chamber of Secrets as the Malfoys’ servant. House-elves are bound to wizarding families and can perform powerful, wandless magic—like apparating in places wizards can’t, including Hogwarts. Dobby is freed when Harry tricks Lucius Malfoy into giving him a sock, a symbolic gift that releases a house-elf from servitude.

To distinguish the options: goblins run Gringotts bank, pixies are mischievous blue fliers (remember Lockhart’s chaotic lesson), and gnomes are garden pests the Weasleys