On 21 August, former NASA engineer and now Halloween costume designer Mark Rober flew into London from Los Angeles.

"I could see the London Eye and I think, 'what in the world am I doing'. This wasn't part of the script," he tells Wired.co.uk.

Until June of this year, Rober was a mechanical engineer at the world's most famous space agency. He had worked at NASA for nine years, seven of which were spent working on the Curiosity Rover.

Now he creates wearable tech Halloween costumes and recently sold his company, Digital Dudz, to the British company that makes Morphsuits, where he now works (nope, we didn't know they were a British invention either).

It all began on Halloween in 2011, where Rober unveiled a costume like no one had seen before. Using two iPads, one on the front and one on his back, he was able to create the illusion of seeing through his body by linking the two using FaceTime.

"I handed my phone to my wife and said, 'people love this at the party, just film this,'" he says. He put the video on YouTube and it instantly went viral, getting 1.5 million views in a day. "Everything has stemmed from that one decision."

By the following Halloween, he was ready to share his invention with the rest of the world. With a couple of friends he created a free app, a bunch of t-shirt designs, and a website selling wearable tech Halloween costumes. After cutting a hole in the shirt and duct-taping your device on the inside, their app would play a video that made part of the t-shirt's illustration look alive.

On 3 October 2012 they went live.

"We spent zero dollars on advertising. We just had a YouTube video and that was it," he says. "We did a quarter million dollars in revenue, just in three weeks."

Since then, the app has been downloaded a quarter of a million times and Rober has left behind a career with NASA and gone full-time with his costumes. He's constantly bubbling with energy during our phone call, half-excited about the adventure he's on but, I'm guessing, also half-astounded at the ridculousness of the whole situation.

"Last year you had to cut a hole in [your t-shirt] and duct tape your phone to your shirt," he says, stressing his words as if to say, 'and people still loved it'.

"It's so ghetto," he jokes. This year they've upgraded and included a pocket to hold the phone. "You don't need to have as many MacGyver skills this year," he says.

New designs for this Halloween include integrating the app with the Morphsuits—Rober holds a patent for the integration of apps with clothing and costumes—and a design that uses your phone's

accelerometer to make it look like your intestines are being ripped out when someone slaps you on the back.

Over the next two years Rober says they'll be using more features in your smartphone to create new costume experiences.

"You know you have disruptive technologies in the tech [arena], we want to be disruptive in the fancy dress industry," he says, laughing. "You've got so many things on there, the accelerometer, near-field communication, Bluetooth, and other sensors […] There are cool interactive concepts [to be explored]."

But surely leaving NASA to design costumes is a strange career move, to say the least.

"It's a little bit scary," he admits. "But at the same time it's such a cool opportunity. It's just one of those things in life, you've just got to see what happens.

"One of the things that always appealed to me about NASA was we were always doing cool stuff that no one's done before," he says, earlier in our conversation. "Granted nothing's as cool as building spaceships, but there is also something cool about getting an e-mail from a guy that says: 'I've never give so many high-fives as I did last night.'"