The Sand Wyrm is a skeleton-type snake, having a bull-like skull as it's head. It is possibly one of the most hated mobs in SAOB as of the 0.4.1 patch.
The Sand Wyrm has a considerable amount of speed. Dealing huge amounts of damage and not being able to outrun makes it a very difficult enemy to fight. The Sand Wyrm can throw you across the entire map if you are standing in the wrong spot, or trap you under itself. Sometimes it can jump up ledges.