An unsuspecting man got a not-so-sweet surprise when he was brutally bitten by a supposedly docile rescued crocodile -- and the terrifying encounter was caught on camera.

The elderly gentleman was just another tourist checking out the "lucky" croc at Indonesia’s Cimory Dairyland, after it was reportedly saved from a flood last week -- but as you can see, the resting croc ignores the man's food offering, and suddenly chomps down on his arm and yanks him into the water.

The footage is straight out of everyone's worst nightmare -- this poor grandpa was tossed around in the water like a rag doll, while onlookers screamed in pure panic.

Miraculously, the man was pulled from the water -- video later shows firefighters rushing him to the hospital with a severely injured arm.

Officials revealed this croc was spotted near a landfill and had laid eggs on land ... so if there’s a female, you know a male’s lurking nearby. They’re warning locals to stay alert -- 'cause there’s solid proof these crocs are anything but gentle!