Strange Snake behavior

This is my 12 year old Amelanistic corn snake Q. He just recently started this behavior. He is eating, pooping and otherwise behaving normaly. Does anyone have an idea why he is doing this. He is in a 75 gallon tank, he can spread out completely without touching on either side. He does have things in his tank to climb on or hide in. You just can t see it in the video. The bird chirping in the background is actually inside the house in a completely different room, not as loud live, just the camera picks u