An elaborately designed crop circle is capturing the attention of residents south of San Francisco, and theories this morning persist about how the crop circle got there, according to a report from CNN

Someone identified simply as "Cannot Say" posted a 2 1/2 minute video on YouTube that shows green flashes of light from what appears to be the field in question.

Local affiliate KSBW reported two friends were driving on Chualar Canyon Road near the field when they witnessed the strange lights flashing on the horizon. The two quickly turned on their video camera, pulled over, jumped a barbed-wire fence, and walked toward the lights until they panicked and sprinted away from the scene.

"Needless to say, pretty wild," the anonymous user posted with the YouTube video. "But we slipped away and it's too good not to share."

The implication that aliens may have something to do with the crop circles has local residents unconvinced. Jim Gillot of Chualar told KSBW that he saw extension ladders and a crew of 30 people in the field last week.

"Every time I drove by I saw them walking around," he said. "It looked like they had little GPS's or something."

The field's property owner was out of town during the incident, and he ordered the field plowed Tuesday.