9. Thestrals
Thestrals are magic beings that appear first in the series when Harry arrives at Hogwarts for the first time, although we can’t see them. They are pulling the “horseless carriages that transport the students from the train station to the castle. Only a person who has witnessed death can see them. Harry can see them after he witnessed the death of Cedric Diggory in the fourth book. But, Harry had seen death before, when Voldemort killed his mother. J. K. actually tried to explain this one, by stating that Harry wasn’t fully aware of his mother’s death, since he was a baby when it happened, but even she admitted that is rather a poor excuse for this magical plot hole.
