In The Canterville Ghost, how are the antics of the ghost amusing as well as pathetic?
While the question of whether or not the Ghost's antics are amusing is in the eye of the beholder, they are clearly designed for comic as well as pathetic effect. In other words, Wilde wants the comedy of his story to lie in more than just the laughs produced by the way the Otis family is oblivious to how they are "supposed" to respond to an English ghost haunting an ancestral home. We know Wilde is playing for laughs because he is so "over-the-top" in his descriptions of the stereotypical ways the ghost tries to frighten the family. For example, he provides the following long description of the Ghost's attempt to get revenge on the Otis boys:
Then, as their beds were quite close to each other, [the Ghost meant] to stand between them in the form of a green, icy-cold corpse, till they became paralyzed with fear, and finally, to throw off the winding-sheet, and crawl round the room, with white, bleached bones and one rolling eyeball, in the character of "Dumb Daniel, or the Suicide's Skeleton," a rôle in which he had on more than one occasion produced a great effect, and which he considered quite equal to his famous part of "Martin the Maniac, or the Masked Mystery."
This quote is meant to do more than show that the ghost is pathetic in his failure to frighten the Americans. Wilde is quite broadly going for the gag in this parody of what you might find in a "haunted house."