Photo via Elias Levy/Flickr (CC-BY)
McQuillen was able to capture the encounter with his GoPro, which shows the terrifying moment when the shark first knocks into him and then circles back for a closer look.
"I was diving off the coast of Santa Barbara at Refugio Point Sept 1st when I was hit in the back, I thought it was my friends playing a joke on me," he wrote in the description of the YouTube video. "I lost grip of my speargun which I quickly retrieved and then it hit me. A HUGE great white which was at least 12ft long attacked me from the left side. It quickly circled around me and I used my speargun to keep it away."
You can hear McQuillen shouting in the video, trying to warn his friends about the shark.
He added: "Extremely lucky to get out of this one alive. I saw blood around me and wasn't sure where it was from, so I swam as fast as I could back to shore. Got a laceration on my right foot in the initial hit, I didn't realized the shark had bit me. The shark bite broke two of my toes."
For proof, he shared the following photo. (Warning: It's graphic.)That was close.