Take some shady characters, a net, a bag full of water and a polystyrene box, and you've got yourself a recipe for a shark-napping. At least that's what officials speculate would have been needed to execute the recent shark heist at a London aquarium.

The investigation is ongoing in the theft of the extremely rare two-foot-long marble shark from Indonesia. It takes on special importance, because the stolen fish is the female half of the only breeding pair of marble sharks in the U.K.

The owner of the $20,000 shark is desperate for its return. "I'm very attached to her," said owner Peter Newman. "I could look for another female but it's difficult as I'm not sure it would mate with the male."

Question Raised: What do you think would be the most difficult animal to kidnap?

If you think stealing a shark is dangerous, check out people running with the bulls after the jump.

Running with the Bulls

    Revelers are chased by Conde de la Corte ranch fighting bulls on the first day of the running of the bulls during the San Fermin festival in Pamplona, northern Spain, on Monday, July 7, 2008. (AP Photo/Victor R. Caivano)

    AP

    Revelers chased by Conde de la Corte ranch fighting bulls, not seen, run on the first day of the running of the bulls during the San Fermin festival in Pamplona, northern Spain, Monday, July 7, 2008. The 'Los San Fermines' festival, held since 1591, attracts tens of thousands of foreign visitors each year for nine days of revelry, morning bull-runs and afternoon bullfights. (AP Photo/Daniel Ochoa de Olza)

    AP

    PAMPLONA, SPAIN - JULY 07: Micky Loomey of New Zealand is attended to by members of the Red Cross after being injured during the first San Fermin running of the bulls on July 7, 2008 in Pamplona, Spain. Fighting bulls are run through the old part of Pamplona for eight days in this fiesta made famous by the 1926 Ernest Hemmingway novel 'The Sun Also Rises'. (Photo by Denis Doyle/Getty Images)

    Getty Images

    PAMPLONA, SPAIN - JULY 07: A runner leads the pack of fighting bulls around a curve during the first San Fermin running of the bulls on July 7, 2008 in Pamplona, Spain. Fighting bulls are run through the old part of Pamplona for eight days in this fiesta made famous by the 1926 Ernest Hemmingway novel 'The Sun Also Rises'. (Photo by Denis Doyle/Getty Images)

    Getty Images

    PAMPLONA, SPAIN - JULY 07: A fighting bull takes the curve during the first San Fermin running of the bulls on July 7, 2008 in Pamplona, Spain. Fighting bulls are run through the old part of Pamplona for eight days in this fiesta made famous by the 1926 Ernest Hemmingway novel 'The Sun Also Rises'. (Photo by Denis Doyle/Getty Images)

    Getty Images

    A runner is attended to after being injured during the first day of the running of the bulls at the San Fermin festival in Pamplona July 7, 2008. REUTERS/Joseba Etxaburu (SPAIN)

    Reuters

    A runner is attended to after being injured during the first day of the running of the bulls at the San Fermin festival in Pamplona July 7, 2008. REUTERS/Joseba Etxaburu (SPAIN)

    Reuters

    Runners sprint next to Conde de la Corte fighting bulls during the first day of the running of the bulls at the San Fermin festival in Pamplona July 7, 2008. REUTERS/Joseba Etxaburu (SPAIN)

    Reuters

    A reveller is tossed by a heifer on the first day of the running of the bulls at the San Fermin festival in Pamplona July 7, 2008. REUTERS/Joseba Etxaburu (SPAIN)

    Reuters

    Runners sprint in front of Conde de la Corte fighting bulls and steers during the first day of the running of the bulls at the San Fermin festival in Pamplona July 7, 2008. REUTERS/Joseba Etxaburu (SPAIN)

    Reuters