Helmeted Bird Monster

This helmeted bird monster is carrying a pencil box and an inkpot in its beak, in which the nun, decaying into a pig, is dipping her pen. A severed foot is swinging from the bird's helmet referring to the horrible corporal punishments which could be expected in hell. The pig, indeed an indictment against the decay of clergy life, is tempting the man who is sitting beside him and it appears that he is drawing up a contract. Is the man possibly selling his soul?