Hedge funder Brett Barna threw a wild “Wolf of Wall Street”-style Hamptons party — awash with Champagne, scores of bikini-clad women and costumed gun-toting midgets — and allegedly trashed a $20 million mansion.

Barna, a portfolio manager at Louis Bacon’s Moore Capital Management, hosted the all-day “#Sprayathon” pool party on Sunday, where 1,000 people doused themselves in bubbly as rapper Ace Hood performed.

Now the furious owner of the 14-bedroom estate in Bridgehampton plans to sue Barna, 31, for $1 million, saying the Wall Street hot shot had claimed the party would be a fundraiser for an animal charity for a mere 50 guests. Plus, Barna is disputing the $27,000 Airbnb rental and is refusing to pay.

The owner, who asked to not be named, told us, “Brett came to me dropping Louis Bacon’s name and saying he was a big deal with the Robin Hood Foundation. He said there would be 50 people at the event and it was for animal rescue. But the only animals there were the people, a thousand of them. They drowned themselves in Champagne, they had midgets they threw in the pool, they broke into the house, trashed the furniture, art was stolen, we found used condoms. So many people were there that the concrete around the pool crumbled and fell into the water. It was like ‘Jersey Shore’ meets a frat party. We are preparing a massive lawsuit . . . We’re waiting to serve him. Brett was last seen on Sunday chugging Champagne with two midgets.” Wild social media posts show partygoers dousing themselves in booze and dancing wildly.

This is an annual bacchanal: Last year #Sprayathon revelers started a brush fire at a Hamptons manse owned by “Hercules” actor Kevin Sorbo.

A rep for Moore didn’t comment, but a source said they raised $100,000 for Last Chance Animal Rescue, and they hired cleaners and left the house in good condition. Barna didn’t respond.

UPDATE: Barna has been fired.“Mr. Barna’s personal judgment was inconsistent with the firm’s values. He is no longer employed by Moore Capital Management,” a spokesperson for Moore Capital Management said in a statement.