Transcript for 'My Little Pony' Loved By Young Girls, 'Bronies'
If you were looking for three words with a high likelihood of alienating a dude in his 20s, you'd do well to go with "My little pony." And yet somehow, this cartoon about pastel ponies has developed a cult following among seemingly Normal grown men. They're called bronies. ABC's David Wright may have been coopted. Reporter: Jake is a motorcycle-riding metallica fan. Staff sergeant Jacob Hughes, I'm 29 years old, I'm from Houston action Texas. Reporter: Also an Iraq war veteran. This is my room. Reporter: Chelsea is 11 years old, quiet, and studious. She wants to be a veterinarian when she grows up. What do Jake and Chelsea have in common? ? My little pony ? Reporter: Both are huge fans of my little pony. For those not familiar, my little pony is a cartoon and toy franchise owned by hasbro. The show mainstream and up for a cameo in a super bowl ad. Apple jack. Sparkle -- Rain dough dash. Piggy the party pony. Reporter: Little girls are the target demographic. The show is about little ponies who face problems, they become friends, and they have to work together to solve every problem. Well animated, well written. Reporter: Surprisingly, grown women and men are into it too. A brony is an older man who likes the show "My little pony." Reporter: It's a slightly touchy subject. They try to paint us as we're pathetic, basement dwellers, people living in their mother's basement. No, I'm not some out of shape, lazy, man-child. I have served my country dutifully for 11 years. I also like pastel-colored, talking ponies. Got a problem with that? Reporter: You know who doesn't have a problem with that? Chelsea. She's intrigued by bronies. I am excited to meet the bronies. But I am a little nervous. Because I've never really met a brony. Reporter: It's hard to fathom the phenom of "My little pony" unless -- Ponyland, here we come! Reporter: You happen to have three little daughters who are obsessed with the show. Just imagine the dad points I scored for wrangling vip passes to pony-con 2015. It's like a star trek convention for my little pony? You have to be careful. When you say my little pony, people think the 1980s my little pony. The next generation? Friendship yes. Reporter: The new one winks at grownups. There are pop culture references, including this nod to "The big lebowski." There's a vast online community connecting. The crowd at pony-con is into it, people letting loose their inner pony. Testing one, two, three. Reporter: The bronies are here in force today. You're a student at mit? Yes. You're into ponies? Yes. Just like any other show on TV. Watching like "Breaking bad." Watching "Game of thrones." I just like "My little pony." What's the term for a female brony? Pegus-sister. Who knew. Reporter: My three pega-sisters seem to be having a great time. Most of it is geared to grownups. 11-year-old Chelsea is having a field day. I'm looking at all the plastic figures. Reporter: Her mom not so sure. Toothpaste? Reporter: She's skeptical of the merchandising. They don't have this much selection at target. Reporter: Even more skeptical of the bronies. I don't understand what a 35-year-old man would have in common with my 11-year-old daughter. Reporter: Jake is here too today. Sporting pinky pie on his shoulder. Clearly not your first rodeo? No, sir. I have been to I think -- if I remember right, this is my fifth or sixth pony convention. And the rest of the year? The rest of the year? You know, I'm just Normal. I'm just Jake. This is big Mac into be, apple jack's big brother -- Reporter: He says when you dig deeper it's not surprising someone like him should be in the show. In the army we have the values loyalty, duty, fs, selfless service, honor, personal courage. Kindness, laughter, generosity, honesty, loyalty. If only we could all smile like pinky pie, the world would be a better place. Reporter: Finally, our fans Jake and Chelsea meet face-to-face. Hello, Chelsea, nice to meet you. You too. I'm glad you're the actual target audience of the show. Yes. Then the outliers. That's really cool. Hope you're going to have fun. Yes. That's the most important thing. It's your show, you're just letting us hang out. Reporter: Afterwards Chelsea told me she feels like a pega-sister herself. At age 11 even she is beyond the show's target audience. She's part of the fandom. Interesting to see how an 11-year-old girl and a 35-year-old guy can have the same interests. Do you find it creepy at all or not? When I first heard about bronies I thought it was a little creepy. But then I met some bronies and I just was totally comfortable with it. And I wasn't weirded out. They seemed like nice guys? Yes. Reporter: The day ends with a fashion show. Unlike any you've ever seen. Tough choice, but the winner is -- Mary! As the father of three little girls, I guess that makes me a reluctant brony too. ? Hello you are my lady ? Reporter: David Wright for "Nightline" in New York.
This transcript has been automatically generated and may not be 100% accurate.