Mosca tells Corbaccio that Bonario, accidentally acquainted with his father's purpose, entered the house with drawn sword and tried to kill Volpone. He was also looking for his father with the same intent to kill. "This act," says Corbaccio, "shall disinherit him indeed!" At that moment, Voltore slips onstage, un-noticed by the other characters. Corbaccio hopes that Volpone will soon die; he has a dram to help him along.
Suddenly, Mosca discovers the suspicious Voltore. Voltore calls the parasite a villain for feigning his loyalty to both himself and Corbaccio. What is this device of a will about which they were whispering? Mosca arrogantly tells Voltore the plot is in his behalf. He insists that he invited Bonario to these chambers to hear the disinheritance so that the son would destroy the father. If Bonario killed Corbaccio, the law would take the son into custody and Corbaccio's funds would be put into Volpone's will, made out to Voltore. "My only aim was to dig you a fortune out of these two rotten sepulchers."
Alas, though Voltore is convinced of this part of the plot, he demands an explanation for the presence of Celia. Casually, Mosca mentions a visitation to be explained later. The pressing point is that the impatient Bonario seized the lady, wounded her, and made her swear to affirm that Volpone had raped her. That pretext would accuse Corbaccio, defame Volpone, and ruin Voltore's hopes.
Corbaccio, who has been counting Volpone's treasure, is hustled out the door by Voltore. They must find Corvino to tell him the news. Volpone and Mosca have nothing left to do but pray for the success of their latest dodge.
The hurtling pace of the third act is picked up again with Corbaccio's entrance. Here the careless, audacious mind of Mosca, displayed under calmer circumstances at the beginning of the act, shows itself calm in the face of disaster. There is a great deal of opportunity for stage business during this sequence. Perhaps when Mosca discovers Voltore skulking around upstage, it is necessary for him to still a violently trembling leg beneath Volpone's bedcovers. Undoubtedly, the old fox, hiding beneath the sheets, is terror stricken. Not so Mosca.
Let us not forget that Voltore is a great advocate. This special pleading of Mosca's is before a competent judge. Voltore has heard of the will and knows that Mosca must have promised that his patron would reciprocate. In the light of such information, the audience is aware of the grandiose magnificence of Mosca's fabrication. It is a lie in every way worthy of its creator.
Once again, Mosca solves his problems by telling some of the truth to all of the gulls. They learn only what Mosca deems necessary to preserve them in a disposition favorable to his purposes. The audience, of course, is aware of Mosca's duplicity. Their delight is twofold. First, under the circumstances, Mosca is impressive in his agility and ability to keep his stories and listeners straight. Second, Mosca is obviously interested in the meaning of truth and the power of words to deceive as well as communicate. When Mosca is telling his half-truths, his language is always filled with ironic puns intended for the appreciation of his fellow plotter, himself, and his audience.
Jonson is also interested in showing that people often see and hear only that which they wish to see and hear. Mosca is a shrewd judge of this trait in his victims. He knows that he cannot fool Voltore with a simple lie. So he emphasizes those parts of the truth that Voltore's greedy disposition will misinterpret. Today, such perception is called a stereotype. All of Jonson's characters are stereotypes. Thus it is doubly funny that one stereotype, Mosca, can smugly comment on the other stereotypes, Corvino, Corbaccio, Voltore, Bonario, and Celia.