The green Snake in the sack

"The dream had been happy up to that point. I was at my house, relaxed, and everything felt light and easy. Then, out of nowhere, a sack was thrown at me, and a green snake burst out of it. It was aggressive from the first second, hissing and lunging at me, trying to bite. I jumped back, my heart racing, and grabbed something sharp. When it struck again, I chopped its head off, and the snake fell still. I stood there breathing hard, shaken by how sudden and random it all was. When I woke up, my heart was pounding and the fear was still fresh. I lay still for a moment, relieved that it was only a dream, though the image of the green snake stayed with me."