Rosencrantz and Guildenstern meet with Hamlet, and try to convince him to give up Polonius's body, which Hamlet has hidden.
Hamlet points out that Claudius's little helpers are like a sponge. Rosencrantz and Guildenstern soak up Claudius's favors now, but Claudius is sure to wring them dry again as soon as he's done.
Finally, Hamlet makes some intelligent jokes implying that King Claudius is a king of nothing, and that his days are numbered. These are lost on Rosencrantz and Guildenstern.