Oklahoma man driving stolen vehicle caught with rattlesnake, uranium, whiskey and firearm: Police Stephen Jennings joked with officers that he was creating a "super snake."

Officers in Oklahoma made a startling discovery after arresting two people at a traffic stop, only to find that their vehicle contained a rattlesnake, a canister of uranium, an open bottle of whiskey and a firearm, authorities said Thursday.

An officer with the Guthrie Police Department had pulled over Stephen Jennings and Rachael Rivera for driving with expired tags on June 26, Sgt. Anthony Gibbs told ABC News. After the officer discovered that Jennings was driving with an expired license and Rivera was a convicted felon in possession of a firearm, both were placed under arrest, Gibbs said.

The vehicle, a Ford Explorer, was impounded because it did not have insurance. It was later discovered that the vehicle had been stolen.

"So when the impound of the vehicle begins and they start moving compartments, here's the rattlesnake in the backseat," Gibbs said. "It was surprising to the officer, obviously."

As the officers continued to search the vehicle, they spotted an open bottle of Kentucky Deluxe whiskey near a firearm, the sergeant said. Then they discovered a container of "yellowish powder" that was labeled "Uranium."

Jennings, of Logan County, told officers that he had the uranium because he recently purchased a Geiger counter to test metals, and the chemical element came with the purchase. He joked with officers that he was trying to create a "super snake," Gibbs added.

It did not appear that Jennings or Rivera were under the influence of the alcohol.

Jennings was arrested on charges of possession of a stolen vehicle, transporting an open container of liquor, operating a vehicle with a suspended license, and failure to carry a security verification form, the sergeant said. Rivera was arrested on charges of possession of a firearm after a former felony conviction.

The snake was taken from the scene and euthanized, Gibbs said, and the uranium was inspected. The uranium did not result in charges because Jennings was in possession of a legal amount.

Jennings was also within his rights to have the snake.

"In the state of Oklahoma, there are certain seasons where you can hunt rattlesnakes," Gibbs said. "This just happens to be one of those seasons."

Gibbs said that this was the first time he'd ever encountered a discovery like this, and that his department has received calls from other municipalities regarding how they handled it.

"Because if we run into it," Gibbs said, "it's gonna be possible that someone else runs into it."

Jennings could not immediately be reached by ABC News.