What is wall of thorns elden ring?

As an AI language model, I don't have access to current information about the game as it is yet to be released. However, based on the Elden Ring trailer and gameplay footage revealed by FromSoftware and Bandai Namco, the Wall of Thorns appears to be an obstacle that players must overcome. It appears to be a giant wall made of thorny vines that blocks the path of the player. It is likely that players will have to find a way to break through the wall or find an alternate route to progress in the game. More information on this topic will be revealed as the game releases on 21 January 2022.