When people rescue animals, sometimes the animals express their gratitude toward their benefactors. We've previously seen this with a dog, a dolphin, and a sea turtle. And now we can see this expression of thanks from a snake.
Two teenage boys in the US found a snake trapped in a net. They patiently cut it free with a knife. When the snake was free, it regurgitated a whole frog that it had swallowed. It was surely a gift offered to the boys to repay them for their kindness. Unfortunately, the video ends before the boys partake of their reward.
Content warning: a lot of foul language.
http://pet-snakes.com/regurgitation-snakes