A Thestral is a magical creature in the Harry Potter universe. Here are some key features of Thestrals:

• Appearance: Thestrals are a breed of winged horses with a skeletal body, reptilian features, and wide, leathery wings that resemble a bats. They have white shining eyes, dragonish faces and necks, and a glossy black mane and long tail.

• Visibility: Thestrals are invisible to those who have not witnessed death.

• Meaning: Being able to see Thestrals is a sign that the beholder has witnessed death and gained an emotional understanding of what death means.

• Behavior: Despite their intimidating appearance, Thestrals are intelligent and loyal to some humans. They are carnivorous and attracted to the scent of blood. They are strong flyers and can carry people anywhere they want to go, and they have a good sense of direction.

• Association: Thestrals are native to the British Isles and Ireland and are associated with wizards who descend from the horse-loving Celtic peoples.

• Use: Thestrals are used to pull the Hogwarts carriages to and from the train station at the beginning and end of the school year. Hagrid is proud of having the largest domesticated herd of Thestrals in the UK.

In summary, Thestrals are magical creatures in the Harry Potter universe that are invisible to those who have not witnessed death. They have a skeletal body, reptilian features, and wide, leathery wings that resemble a bat's. Despite their intimidating appearance, they are intelligent and loyal to some humans, and are used to pull the Hogwarts carriages.