I would certainly help it. And after I did I would look it squarely in the eye and say, "Today is not your day to die, my friend. Go in peace." And the snake would go on to tell the story of the pink biped that saved it from a terrible fate. And snakes would pass the story on. Until no snake ever bit a human again. Snakes and humans would live in peace forever more. And when the alien reptiles came to conquer Earth, the snakes would tell them to leave the humans alone. And of course, the reptilian aliens would respect their terrestrial cousins.
And that's how I saved the world from an alien invasion.