Black holes are rarely seen creatures that operate in the shadows. If anything is left lying around or falls off a table, a black hole might (for they are decreasing in number) run past and swallow it up. The reasons for them doing so are unknown but what is odd is that some of them redeposit what they've swallowed at a different location. Not to be confused with thieving gypsy bastards.
"Has anyone seen my pen?" - typical response after a black hole feeding session.