This has happened to me. But an Osprey. It took the fish out of the water and stripped almost 100' of fly line off my reel. The hook was still in the fish. It was like a kite but with a bird attached. I finally grabbed the last part of my fly line and ripped the hook out. I think it took about 3 seconds for the bird to take all that line off a Ross reel.
About 7 people were on the shoreline and saw the whole thing happen. Once I realized that I was going to keep my fly line, and that I didn't hook the bird, my anxiety settled down and I yelled out, "You're Welcome!". It generated audible claps and cheers from audience on the shoreline. I thought it was a once-in-a-lifetime situation but I'm confident I could easily duplicate it again if given the opportunity. The location has crystal clear water --- you can see 30+ ft. in spots. The ospreys make their nests along the shoreline and the fish hunker on the bottom because they are aware of the predators. A fish is hooked, it rolls as it gets close to the surface, and the flash of the fish ignites a response from the Ospreys. They are highly efficient.