When the Fat Lady refused to let Sirius Black into the Gryffindor Tower, he attacked her with the knife, slashing her portrait. Once he manged to sneak into the tower, he used it to try to kill Peter "Wormtail" Pettigrew in the tower in 1994, in Animagus form of a rat named "Scabbers". Unfortunately Ronald Weasley thought that Sirius went over to the wrong bed and tried to kill him. It is unknown what Sirius Black did to his knife afterwards.
- Harry Potter and the Prisoner of Azkaban (Mentioned only)
- Harry Potter and the Prisoner of Azkaban (film) (Deleted scene)