The burly man with a shock of silver curls and a scruffy beard gesticulates wildly on Milan's Piazza del Duomo, unleashing a sprawling diatribe against the political establishment.
"Send them home, send them home!" Beppe Grillo cries, as tens of thousands of supporters send up a deafening cheer.
Crisis-hit Italians are fed up. And no one is tapping that vein of outrage better than comic-turned-political agitator Grillo and his anti-establishment 5 Star Movement.
Grillo fills piazzas from Palermo deep in the south to Verona up north with Italians who seem to get some catharsis from his rants against the politicians who drove the country to the brink of financial ruin, the captains of industry whose alleged illegal shenanigans are tarnishing prized companies - and the bankers who aided and abetted both.
On the last day of official campaigning, tens of thousands of people filled an enormous Roman square, while more followed on live streams or on maxi-screens set up in towns throughout the country - dwarfing the closing rallies of his main competitors.
Grillo's campaign is significant not only because he shows strong chances of being the third - some project even the second - party in Parliament after the Sunday and Monday vote. The 5 Star Movement is the strongest protest party ever seen in Italy, creating a fluid and unpredictable electorate at a time when the nation needs a clear direction to fight its economic woes. A strong election showing for Grillo could hinder coalition-building efforts among mainstream parties, leading to a period of political paralysis.
`'Grillo cannot be underestimated," said Renato Mannheimer, one of Italy's most respected pollsters. "He is very important."
`'More than protest, Grillo is an expression of disappointment in this political class. His followers are not anti-political. Most are interested in politics, but these politicians disgust them."
The most recent polls of voter sentiment show Grillo in third place, with 17 percent of the vote, behind Pier Luigi Bersani, the center left candidate for premier, who enjoys 33 percent of the vote and Silvio Berlusconi's center-right coalition with the Northern League in second with 28 percent. Premier Mario Monti's centrist coalition is preferred by 13 percent of voters in the COESIS poll of 6,212 respondents, which had a margin of error of plus or minus 1.2 percent.
A trading scandal at Italy's third-largest bank, Monte dei Paschi di Siena, as well as accusations of corruption at the government-controlled Finmeccanica and the Italian gas and oil giant Eni have served recently to push a stream of outraged voters into Grillo's arms.
`'What happened with the banks, with MontePaschi, reignited interest in Grillo. Grillo is credible on those issues. In Italy, banks and politicians are the most disliked actors on the scene," said Roberto D'Alimonte, a political science professor and commentator for financial daily il Sole 24 Ore.
Critics say that Grillo is good at tapping into voter anger - getting to the heart of everything that's wrong with the ruling class - but has few constructive ideas of his own for helping Italy emerge from crisis. Monti, in particular, has called Grillo's success his `'greatest worry."
`'The people who vote for Grillo and who would vote yes on a referendum on exiting the euro should then fill the piazzas to protest against the catastrophic state that would befall Italy," Monti said recently. `'It takes protests, but also proposals."
Pollsters say Grillo's true strength could be greatly underestimated in the polls because a vote for Grillo is being viewed by those disgruntled with Italy's quagmire as a vote of conscience.
`This is not a military revolution, this is a civilian revolution," said Claudio Pollini, a 45-year-old engineer ahead of the Rome rally. `'This is not something that is left and it is not right. It something for all people in Italy."
While the 64-year-old comic from Genoa has firmly captured the Italian Zeitgeist, many of his messages are raising concern among seasoned political observers, not just political opponents. Grillo's staunchly anti-euro stance has tapped growing animosity toward the EU, which is viewed by many Italians as the architect of painful austerity.
It remains unknown how members of Grillo's movement will behave once in parliament. Grillo himself is not seeking office, being barred from becoming a lawmaker due to a manslaughter conviction for a 1981 car accident that killed two friends and their young son.
Certainly, Grillo has shown no willingness to cooperate with existing parties, and many of his candidates lack political experience - which the movement's supporters consider to be an advantage.
Grillo is the top pick among first-time voters who find in him an expression for their rebellion. He is also picking up support from disaffected backers of the populist Northern League, who are unhappy that their leaders teamed up with Berlusconi.
It is unclear how many of the 30 percent of Italy's undecided voters will throw in their lot with the comic. Mannheimer believes they will be many.
Grillo's campaign to upend Italian politics is anything but routine.
In a nation where the people get most of their information from television - dominated in part by Berlusconi's media empire - Grillo eschews TV, a medium that shunned him for years, and forbids candidates running under his banner from appearing on air at the risk of being booted from the movement.
He seeks more direct contact with his followers, in piazzas and through his blog, one of the most popular in Italy. He approaches his public appearances as he does his stadium comedy routines: He speaks and the audience listens. The one-way flow has led to criticism that he refuses to engage in debates about his ideas with opponents or even supporters - though that has done little to stem his rise.
`'However it goes, and whoever wins, this will be remembered as the elections of Beppe Grillo," columnist Beppe Severgnini wrote in Corriere della Sera on Thursday.