A weakly thrown apple grazed Gregor’s back but skidded off harmlessly. But another one, thrown immediately thereafter, drove hard into Gregor’s back. Gregor wanted to drag himself away, as if he could make this surprising and unbelievable pain disappear with a change of location; alas, he felt instead as if he were nailed to the floor, and lay stretched out in complete confusion of all his senses.The apples already had me thinking of Adam and Eve, then Gregor's being stretched out and nailed made me think of the crucifixion. And of course he has already been transformed to a lower order of being, rather like God becoming a human being.
Then I remembered this.