"My heart, it just left my body," said Nicole Pinheiro, who shared the video. "And I showed my mom and she burst into tears. She was like, 'I can't believe that this is the world now.'"
Investigators say the overwhelming amount of shares helped put the incident on their radar.
Patterson Police arrested Garret Haile before school on Friday. He was 17 when the video was shot, and just turned 18 last week. Haile was booked into jail on a felony animal cruelty charge. Investigators say whoever recorded the video may also face charges.
Police said they expect Haile will face the charge as a minor.
As for the cat in the video, police are looking into where Haile threw it -- whether it's in Stanislaus County or somewhere else.