Nearly Headless Nick, also known as Sir Nicholas de Mimsy-Porpington, is a ghost in the Harry Potter series. He is the resident ghost of Gryffindor House at Hogwarts School of Witchcraft and Wizardry. Nick is famous for his nearly severed head, which gives him his nickname. He is friendly and often interacts with the students, providing guidance and support. Nick's backstory reveals that he was executed for being a wizard who could not perform magic properly. His ghostly appearance reflects his tragic fate, as he is stuck between the living world and the afterlife. Despite his unfortunate condition, he maintains a cheerful demeanor.