The snakes on the porch

"I was at my parents' house, but the back porch was longer than it should be, like it went on into a field. Two snakes were fighting near the steps, one dark green and one a dirty yellow, thick as my wrist. They kept knotting around each other and the sound was awful, this wet dragging noise on the boards. I wasn't trying to stop them. I think I was supposed to be watching them for someone, maybe my brother? I kept looking at my phone to check the time, which made no sense because the screen only showed a color. Then a jump, and I was inside behind the glass door, and somehow the snakes were bigger. The yellow one hit the glass and I felt it in my chest. I was pretty sure I'd left the door unlocked earlier but my hands wouldn't move to check. Someone behind me said "just let them finish," really calm, and I couldn't turn around to see who. I woke up with my sheet twisted around my leg, heart pounding, and lay there a while listening to the quiet."