Quote from : Harry Potter and the Half-Blood Prince Movie

Rubeus Hagrid: [talking about Aragog] I had him from an egg, you know? Tiny little thing he was when he hatched. No bigger than a Pekingese. A Pekingese, mind you!
Horace Slughorn: How sweet! I once had a fish... Francis. He was very dear to me. One afternoon, I came downstairs and... it vanished. Poof.
Rubeus Hagrid: That's very odd, isn't it?
Horace Slughorn: Yes, doesn't it? But that's life! I suppose, you - you go along with and suddenly... poof.
Rubeus Hagrid: Poof.
Harry Potter: Poof.