At Supper Not Where He Eats?

Hamlet, therefore, tells King Claudius that Polonius

is at supper, only "not where he eats, but where he is eaten." The worms are eating the dead and hidden Polonius. Just like everyone else, he has fattened himself up for the enjoyment of the maggots. ... And if a beggar eats that fish, then he has eaten part of a king.

What does Hamlet mean when he says Polonius is at supper?

*Hamlet tells the king that Polonius is at "supper", meaning he is the supper for the magots in the ground. *He reveals that the body is stuffed under the steps and they will be able to find him by the smell. *Claudius thinks he is really crazy at this point.

When Hamlet tells the king that Claudius is at supper by stating not where he eats but where he is eaten a certain convocation of politic worms are e'en at him this response is characterized by?

Not where he eats, but where he is eaten. A certain convocation of politic worms are e'en at him. Your worm is your only emperor for diet. We fat all creatures else to fat us, and we fat ourselves for maggots.