As an enormous crowd gathered outside Rome's San Giovanni basilica on Saturday, comedian Beppe Grillo had every reason to be jubilant, but the thought of bringing down Italy's political order appeared to make him pensive, even melancholy.
"It's been like this up-and-down Italy - we are witnessing a change in civilisation, not just politics," he said.
"Italy has turned its back on its political class and a new language of community, identity and honesty is filling the gap."
Minutes later, a wilder Grillo took the stage to a rock-star welcome before at least 100,000 cheering fans, yelling his movement would rip open Parliament "like a tin of tuna" when it sends an army of activists - analysts predict more than 100 - into the Senate and Lower House after Italians go the polls today.
The massive rally was the climax to a marathon tour of packed piazzas which has pushed Grillo's poll ratings towards 20 per cent, panicking pundits who had predicted a market-pleasing outcome in which centre-left leader Pier Luigi Bersani would form a coalition with outgoing technocrat Prime Minister Mario Monti.
Silvio Berlusconi, hitherto seen as the potential spanner in the works, slipped back in the final days of campaigning, drawing flak for making lewd remarks to a woman during a speech and condoning bribery in a TV interview.
Grillo has surfaced as the new bogeyman for the markets, his popularity threatening gridlock in Parliament or a weak centre-left coalition which will collapse within months.
His manifesto combines pro-environment policies with a crackdown on parliamentary privileges, a living wage for the jobless using cuts from military spending, slashing top managers' wages, broadband for all, bike lanes and the right for priests to have children "so they don't touch other people's".
But what has spooked the markets is his commitment to hold a referendum on leaving the euro and a temporary freeze on interest payments on Government bonds, which could lead to default.
-ObserverBy Tom Kington