BY Monday morning, Michael Cugini would be back at his desk at a major Wall Street firm, another high-powered cog in the engine of finance. There would be men on his left, men on his right, all yelling into their phones and scanning the stock ticker.

But Mr. Cugini bore unseen scars beneath his crisp custom suit. Twenty-four hours earlier, Mr. Cugini (nickname Cujo) was shirtless, face down, crawling through a 40-foot-long pit of cold mud, while being electrified by low-hanging wires. He also scaled a 15-foot-high wall, ran 12 miles and underwent something called an Arctic Enema, in which he jumped into a Dumpster filled with ice water, dyed neon green, and swam under concertina wire.

Two and a half hours after he began, Mr. Cugini crossed the finish line, bloody but unbowed. He had a Dos Equis to celebrate.

“There’s always a lot of moaning on Monday morning,” said Mr. Cugini, 31, a small man with a bald head and a strong grip. “And I just think, ‘Come on, what did you do this weekend?’ ”