Norbert the Norwegian Ridgeback
Norbert? Funny name for a very dangerous dragon, you might say. But as you’ve probably noticed, Hagrid sees scary creatures in just the same light as we see cute little kittens and puppies. Baby Norbert came to Hagrid as a dragon egg, and hatched into a Norwegian Ridgeback - a particularly dangerous breed of dragon. Hermione wisely points out that Hagrid might not have the best home for a fire-breathing dragon, what with living in a wooden house, but Hagrid loves Norbert anyway.
To hatch a dragon egg, you must keep it in a fire - because dragons' mums like to breathe on their eggs.