Out of all of Spider-Man's villains, Mysterio has always been the trickiest. Quentin Beck has performed feats of illusion that have fooled the web-slinger time and again, despite his lack of superpowers. Mysterio's greatest trick might possibly be resurrecting New York's biggest crime boss.
Beck's monumental achievement occurred in Amazing Spider-Man #618-620, by Dan Slott, Marcos Martin and Javier Pulido. The story began by establishing the various losses within the Karnelli crime family. Each major member of the Maggia died of various causes, including their most famous leader, Silvermane. It was Mister Negative, however, who dealt the largest blow to the Maggia. Indeed, in Amazing Spider-Man #547, by Dan Slott and Steve McNiven, Martin Li killed nearly every adult male in the Karnelli family with his infamous "Devil's Breath" poison.
With very few members left, the Maggia were left with "Baby" Bruno Karnelli as their boss. Business was bad, as Mister Negative and his gang were wiping out all of the Maggia's money-laundering schemes. The situation became so dire, that when Spider-Man took down some of Mister Negative's men, he barely noticed that they were attacking a Maggia casino. Clearly, this gang war was very one-sided. Bruno Karnelli's consigliere, Carmine, had enough, bringing in his long-dead relatives to take care of business.
Indeed, all of these formerly-deceased Maggia members were alive and well, even Silvermane. Carmine claimed that Mysterio had helped each of these men fake their deaths. Reunited, the Maggia leaders led an assault on Mister Negative's gang. Negative's men were taken completely by surprise, including Hammerhead, who was loyal to Silvermane. During a battle between the two gangs, the police and Spider-Man interfered.
As the web-slinger fought Silvermane, the truth behind the Maggia's resurrections was revealed. All of the leaders who returned were actually robots designed by Mysterio. Beck used high-tech special effects to simulate the Maggia leaders' return so that Carmine could control the mob. As part of the act, Mysterio led Spider-Man to believe he accidentally killed one of the gang members.
In order to further crush the wall-crawler's spirit, Mysterio led Spider-Man into a trap, containing several robot duplicates of crime lords such as the Big Man. All of these gangsters killed each other, horrifying Spider-Man. Yet, when the web-head unmasked the Big Man, George Stacy's face was revealed. It was at this point that Mysterio went too far since Spider-Man saw right through his deception.
Meanwhile, Beck made "Silvermane" kill Carmine in front of the rest of the mob, taking over through this imposter. Using the robot, Mysterio commanded that the Maggia consolidate all of their money in one location. Once there, Beck collected all of his money before calling Mister Negative and telling him where the Maggia members were hiding.
In a dockside opera house, Spider-Man became entangled in an all-out brawl between Mister Negative's forces and the Maggia. Ultimately, Mysterio blew up the building and attempted to flee by boat. Yet the web-slinger caught up with Beck, blowing up his boat and all the money on board. Although Mysterio escaped, Spider-Man still foiled his plans. This case illustrates how Mysterio is one of Spider-Man's most dangerous villains, even without any real powers. Beck never actually resurrected anyone, but he did an extremely convincing job making it appear that he had. Other gang members, Mister Negative, the police and even Spider-Man were fooled by how well-designed these robot gangsters were. Mysterio was able to use this illusion to take over the mob, which could have made him a powerful crime lord.
Of course, Mysterio simply wanted to steal all of the Maggia's money, which he nearly accomplished. Using his unique parlor tricks, Beck played both sides of this gang war against each other. Mysterio took off with the Maggia's money and sent them to their deaths, demonstrating the true power at his command. The Maggia may have been a dying enterprise, but even Mister Negative, the head of a successful criminal empire, was fooled into Mysterio's hands. Overall, Mysterio's proficiency with smoke and mirrors proves just how dangerous he is.