Thestral Harry Potter Creatures. The Thestral is a breed of winged horse with a skeletal body face with reptilian features and wide leathery wings that resemble a bats. A Thestral is usually only seen by someone that has witnessed death.

Now thestrals. Harry Potter and the Half-Blood Prince. Thestrals are undeservedly known as omens of misfortune and aggression by many wizards because they are visible only to those who have witnessed death at least once and fully.
Acromantula A gigantic spider that is capable of human speech.
You can find Goblins House Elves and Dementors that chills the air even you just mention their name along with many other creatures in this category. Thestrals are only visible to people which witnessed death before and accepts death as a reality. Thestrals are a kind of magical creature which has wings on horse body and lizard-like face. People used to think they were bad omens that seeing them meant bad luck but this is just superstition.