Tom “durrrr” Dwan (pictured) is no stranger to wild swings at the poker tables. After all, the 27-year-old pro routinely bets more pre-flop than what most people earn in a year. But, one recent session at the StarWorld Casino in Macau has earned the notorious distinction of being the worst in his career, costing him millions. Yet up until recently, the amount Dwan lost was unknown.

Last month, Dwan Tweeted about the session gone horribly wrong: “In Taiwan for the 1st time ever… Not leaving the airport tho. Maybe next trip. Had my biggest loss ever yesterday.”

Dwan’s loose-aggressive style has caused him to take some serious beatings in the past, so it was clear that the downswing would be big. Now, sources who were watching the game are reporting that the “loss” to which he referred was a heart-stopping $4 million.

According to CardPlayer, Dwan had been up for over 24 hours playing a marathon session short-handed. But, of course, who needs sleep when you have the sting of a multimillion-dollar loss keeping you awake? The source wasn’t exactly sure which game was being played, but said that the pots didn’t drop below $40,000 for hours.

Macau has emerged as the go-to destination for ultra high-stakes live poker action. The area is a special administrative region of China, enjoying a high level of autonomy, and is the only place in the country where gambling is legal. The territory is heavily dependent on casinos and tourism and attracts whales from the Chinese mainland who don’t bat an eye at splashing around millions of dollars on a few hands of poker.

The bloodbath in Macau aside, Dwan has seen his fair share of ups and downs. One of the biggest hits to his bankroll came in 2009, when he dropped an eye-popping $3 million in a week, losing most of it to a yet-to-be unmasked“Isildur1”over the course of just 13,000 hands.

The massive loss might throw a dark cloud over the unfinished Durrrr Challenge, which was recently revived and saw a bit of action. According to the terms of the original agreement, Dwan would face off against Daniel “jungleman” Cates (pictured) over a span of 50,000 hands, playing high-stakes heads-up matches. If at the end of play, Cates is up by just $1, Dwan will owe $1.5 million on top of his winnings. If “durrrr” comes out on top, he’ll take home a lesser sum of $500,000.

In their most recent battle, the pair played 1,500 hands, with Cates taking Dwan for around $200,000. Cates already holds a substantial lead in the challenge with around 30,000 hands remaining.

Of course, things don’t always go so badly for the young grinder. Last year, he reportedly dragged a mammoth $3.8 million pot against a wealthy Chinese businessman at StarWorld. According to railbirds, Dwan held A-10 versus his opponent’s A-2. The flop came A-10-2 and all of the money went in. When the turn and river blanked, Dwan raked in a mountain of plaques.

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