Boggarts are fictional creatures from the Harry Potter Universe.
Boggarts generally are mischievous creatures, but can be helpful when in the right mood. They respond well to food, but understand when they are being insulted and don't take kindly to that at all.
The Boggarts true form is unknown for when a person sees a Boggart it takes on the shape of whatever is most frightening to the person viewing it. The only way to defeat the Boggart is to laugh at it, and as such, the best spell to use would be Riddikulus to force the creature to change into something humorous. When defeated the creature bursts into smoke and nothing else remains.