"You heard wrong. I'm the complete opposite," Hart shot back. "Jimmy, I'm gonna show you how fast black people are in a second... And I bet my life if you bring out something crazy, the roots will be right behind me."
From the very start, Hart was having none of it, and ran off the stage when Irwin brought out a cuddly baby ostrich. So one can imagine how he reacted when they brought out two snakes right afterward.
Both Fallon and Irwin tried to coax Hart back on stage to hold one of the snakes, but the comic stood firm in his refusal to mess with wildlife.
"Let me tell you what I've gotten really good at in my life: saying no," Hart explained as the audience tried to egg him on by chanting, "Do it! Do it!"
For one moment, it seemed like Hart was considering it, and asked Irwin if the snakes bite.
"Well… they can bite, but they won't," Irwin replied cautiously.
"You lost me at, 'Well,'" Hart shot back, walking further away.
When the nature conservationist brought out a tarantula named Big Red, Fallon joined Hart in his apprehension, running up and standing flush with a pillar to avoid the spider.
"I'm gonna be honest with you, you better stay your ass over there," Hart threatened Irwin from distance.
"He's 14 years old!" Fallon interjected, also having fled from the spider.
"I don't care, Jimmy!" Hart shot back. "It's your birthday, you should hold that spider!"
After a while, Fallon sucked it up and sat down at the desk and let the furry arachnid crawl on his hand while sweating profusely. But Hart did his best to freak him out worse by trying to startle the spider by yelling and slamming his hands on the table.
Eventually, at the end of the segment, a super nervous Hart was finally coerced into letting a falcon land on his arm while wearing a massive leather glove, and no one has ever looked more terrified.
ET's Kevin Frazier caught up with Hart at the premiere of his upcoming comedy, Night School, at the UrbanWorld Film Festival in New York City on Wednesday, hours after the Tonight Show taping, and the comic opened up about the experience.
"I'm not gonna lie, I wasn't as nice a participant as I probably should have been, because of the animals that were there," Hart admitted with a laugh. "They had tarantulas, they had snakes, they had ostriches, a falcon. Everything black people don't like was there."
Kevin Hart's new comedy Night School, co-starring Tiffany Haddish, hits theaters Sept. 28. Check out the video below to hear more from the comic about his upcoming film.