He has held the world's largest hairball in his hands, watched the "rubber boy" contort himself through the head of a tennis racket and is an expert on shrunken heads.
Despite the bizarre experiences, O'Brien said he's not immune to being grossed out.
O'Brien will be at the Fourth Annual Sideshow Gathering at Inkin' the Valley in Wilkes-Barre from Sept. 1-4. He said the tattoo gathering is the a good opportunity to catch up with those who go beyond the definition of normal.
"It's a very unusual, cool event and I'm hoping to walk out of there with a couple acts I can book for television, two or three for our cartoons and five or six for photos," O'Brien said.
But there are limits.
O'Brien isn't looking for Jackass or Fear Factor stunts. After all, Ripley's is well-respected and the acts must be suitable for the entire family.
"We take the high road and we don't go for the total gross outs," he said. "If we like an act, we analyze it and send it to our review committee to make sure it won't offend anybody. We want this to be for families.
"I'm looking for anything that will make people say, 'I don't believe that.' Ripley's is all about the truth and you can believe it or not."
In other words, if you can lick your own elbow or own a two-headed cow, you might fit the Ripley's mold.
Those acts that fit the Ripley's brand may be used to promote the company's new book due out this fall. Others may appear on Ripley's television shows or in cartoons.
The search isn't limited to those who are double-jointed or animals with multiple heads. There's also an art form to the freaky.
The art aspect is O'Brien's favorite part of the job.
He has witnessed a full-size Rolls Royce made from 1.7 million matchsticks, a reproduction of the Mona Lisa made out of toast and a limousine completely covered in European coins.
Some of the Ripley's displays also incorporate history, such as the torture equipment from Medieval times. Those artifacts include an iron mask worn by people who talk too much and a steel mask for bad musicians.
"It's a mask with a metal clarinet attached to the front and they clamped the person's fingers to it. They walked wearing this musical humiliation device," O'Brien said.
Acts have already registered for the Wilkes-Barre show, and the schedule includes The Great Nippulini and a world record sword swallowing attempt.
O'Brien said the show isn't for wannabe freaks who want to hit it big.
"These are people who are trained to perform and they are very precise acts that can kill you if you're not careful," he said. "We don't condone people who try to put an act together 10 minutes beforehand to try to impress us.
"This isn't amateur night. It's an art, not something you do just to be goofy."
IF YOU DECIDE TO GO
The 12th Annual Inkin' the Valley Tattoo Convention will be held from Sept. 2-4 at the Ramada Plaza Hotel, Public Square, Wilkes-Barre.
The event will feature live music, tattooing by the nation's top tattoo artists and a tattoo contest. Private seminars for tattoo artists will also be conducted.
The 4th Annual Sideshow Gathering will be held from Sept. 1-4 in conjunction with Inkin' the Valley.
For a schedule of events, visit www.knddesign.com/tsg/home2.html

