My wife is Latina and translated it roughly as follows (and I quote from memory from last night when she gave it a listen):
"Whatever happened to the quicksand? Remember when we were kids? It was in the movies all the time. Someone is walking along or running through the jungle and -- bloop! -- they sink into the quicksand. Then there just happens to be a vine nearby and someone else comes along and rescues them. And they say all the time, 'Don't move or you'll just sink faster!' Move? Where would I go? Or it's a bad guy and he just disappears and it's a convenient way to get rid of him. So where did it go? Did they build something over it? A shopping mall? A parking lot? What happened?"
Here is the George Carlin monologue on quicksand:
http://www.songzilla.co.uk/song.php?id=25217790