Riddikulus is a charm that is used in defence against a Boggart. It causes the creature to assume a form that is humorous to the caster, thereby counteracting the Boggart's ability to terrorize. Boggarts are defeated by laughter, so forcing them to assume an amusing form is the first step to defeating them.
Professor Remus Lupin taught this to his third-year Defence Against the Dark Arts class. Thanks to Lupin's teaching, Harry Potter was able to use this against a Boggart in the Triwizard Maze in 1995.
Boggarts
| Person | Fear | Riddikulus | Film changes | GBA version changes |
|---|---|---|---|---|
| Albus Dumbledore | The corpse of his sister Ariana Dumbledore[1] | Omitted | Omitted | Omitted |
| Seamus Finnigan | A banshee | She lost her voice. | Omitted | Omitted |
| Hermione Granger | Professor McGonagall telling her that she failed her exams. | N/A (broke down and left) | Omitted | Omitted |
| Neville Longbottom | Severus Snape | Snape was wearing Neville's grandmother's clothes. | Snape | Snape |
| Remus Lupin | Full moon | A cockroach | Turns into a balloon. | Omitted |
| Harry Potter | A Dementor | Smoke/uses Patronus. | Omitted | Omitted |
| Parvati Patil | A mummy | It tripped over its bandages. | A giant cobra that turned into a jack-in-the-box. | A normal cobra that tied herself in her tail. |
| Tom Marvolo Riddle | His own dead body | Omitted | Omitted | Omitted |
| Dean Thomas | A hand that moves by itself | Caught in a mousetrap | Omitted | Omitted |
| Molly Weasley | Dead family/friends | N/A (was too shocked to cast it) | Omitted | Omitted |
| Ron Weasley | Giant spider (or any spider for that matter) | No legs | The spider is given roller skates | The spider is given roller skates |
Appearances
- Harry Potter and the Prisoner of Azkaban (First appearance)
- Harry Potter and the Prisoner of Azkaban (film)
Etymology
"Riddikulus" is an adaptation of "ridiculous".