FRESNO, Calif. -- A surveillance video has started to make its rounds all over the world on the internet as well as social media. Once you catch a glimpse of it, you can see why.

The surveillance footage shows a man walking into a Starbucks wearing a Transformers mask and wielding what appears to be a gun, a buck knife, and a yellow bag. The gun was later discovered to be fake.

The man in the mask approaches the barista behind the coffee bar, appearing to demand money. This is when an unassuming customer decides to spring into action.

The customer, now identified as 58-year-old Cregg Jerri, was enjoying his Starbucks order when the masked man entered the store. He seems to pause for just a second before turning to grab a nearby chair. He quickly but quietly makes his way over to the unsuspecting robber and starts striking the man with the chair.

A scuffle between the two men resumes, and Jerri was stabbed in the neck, but not long before he was able to get the knife away from the other man. He swiftly retaliates, stabbing the robber multiple times.

The robber, now identified as 30-year-old Ryan Michael Flores, escaped the scene but was later arrested by police. Jerri had to get a couple stitches in his neck but is expected to make a full recovery.

Flores is in critical, but stable condition and will go to jail after he is released from the hospital.

For more information, check out the CBS 47 article.