It was late Sunday evening at Pullman Yards, a former fertilizer plant and industrial complex that now serves as an entertainment venue on the east side of Atlanta, and the YouTuber Kyle Forgeard’s path to victory in a glammed-up fantasy football championship was narrowing.

Rubi Rose, a rapper and internet personality from Lexington, Ky., had established a commanding lead as the Bengals-Chargers game barreled toward halftime, and Mr. Forgeard’s chances of winning back-to-back championships, which seemed good earlier that day, were fading.

Mr. Forgeard, who is known for his pranks and podcasts as part of the group the Nelk Boys, sat on a plush black leather sofa watching an enormous television screen, his eyes fixed in earnest concentration, as people buzzed around him. Nearby was Arthur Kulik, known as Jimmy Gambles, who is Mr. Forgeard’s right-hand man and his closest adviser in the game.

“I don’t know about the other teams, but this is very serious to me,” Mr. Forgeard said. “I want to repeat. I’m trying to win.”

That was the scene at the second annual PrizePicks World Championships, an event billed as the “ultimate fantasy competition” in which celebrity-led teams go head-to-head in a daylong contest of daily fantasy football skill.