Almost looks to me like it somehow grew with a vine wrapped around it, or it around a vine?? I found this twisted small tree last year while shed hunting.
You beat me to it, I was about to say the same thing... a vine when young. I have seen trees like this.
If it had grain to match I wonder about wedge splitting corkscrew lengths. Make for interesting table legs, walking sticks ect.
Like JDU and Yawner, I would be more inclined to think a vine wrapped trunk. We see that here as well.
