She certainly didn't become "Rowdy" overnight.
UFC Women's Bantamweight champion Ronda Rousey is the UFC's biggest star. She's graced the cover of magazines, appeared in Hollywood blockbuster films, and she's slaughtered every single one of her opponents by way of stoppage en route to a 12-0 career inside the cage.
In 2010, the Olympian made her amateur MMA debut for Combat Fight League's Ground Zero, needing only 23 seconds to submit Hayden Munoz, proving she was special all along. You can watch the video footage above, but make sure not to blink.
Rousey is set to defend her title against Holly Holm at UFC 193 in Australia.