Sean Smyrichinsky was minding his own business zipping around Pitt Island south of Prince Rupert, British Columbia on his underwater scooter. He was just looking for sea cucumbers, but instead, the diver was faced with a massive and mysterious object that just might be an explosive device.

"I found this big thing underwater, huge, never seen anything like it before," Smyrichinsky recalled in a report from Vancouver Sun.

The sight was so strange that he truly had no idea how to place what he just discovered. At first, the experienced diver thought he was seeing something otherworldly.

"I came up telling all my buddies on the boat 'Hey, I found a UFO. It's really bizarre.' And I drew a picture of it, because I didn't have a camera," he explained.

A more likely explanation presented itself a few days later, when he talked to some fishermen, one of whom suggested the mysterious object just might be a missing explosive device from decades ago.

"Nobody had ever seen it before or heard of it, (because) nobody ever dives there," he said. "Then some old-timer said 'Oh, you might have found that bomb.'"

According to a report from CNN, it was in February 1950 that a Convair B-36B airplane was flying from Alaska to Texas. The plane was carrying a dummy Mark IV nuclear bomb with lead, uranium and TNT, but not the plutonium necessary to detonate.

When the engines began experiencing problems, the plane began descending in face of the emergency. The 17 crew members parachuted to save themselves, but before jumping, they jettisoned the nuclear weapon. No one has seen the bomb since - until perhaps Smyrichinsky.

There are skeptics though.

Dirk Septer, an aviation historian from British Columbia, told BBC that the location of the recently-discovered object is incorrect given the data known about the missing bomb.

"It could be anything," Septer said. "Whatever he found, it's not the nuke."