[Well the cartoons she seen never actually show the hero getting sucked into said black holes, so she guesses they bad things.]

You get sucked up like a straw in a milkshake and you whoosh around space, all over the place! Then the black hole spits you back out and you feel all dizzy, but you feel so dizzy that you need to stop playing for a little. That's a black hole, they're very bad!