Burrowing: Creatures using burrowing speeds treat the ground in combat much like creatures with swim speeds would an aquatic environment except that instead of Swim checks there are Climb checks, instead of Flowing Water there is Seismic Activity, earthen material is always opaque unless exclusively noted otherwise, freedom of movement only assists creatures in these circumstances if they also have a burrowing speed, creatures on the ground always have "firm footing" assuming nothing alters gravity or the ground on which they stand, and weapon attacks treat earthen material as total cover from all directions. Thus, you must have at least some part of you sticking out of the ground to fight non-burrowing creatures while burrowing or must have both freedom of movement and a burrowing speed, though this still means foes still have total concealment from a fully submerged creature unless they are also burrowing and adjacent.

When the creature burrows, it can pass through stone, dirt, or almost any other sort of earth except metal as easily as a fish swims through water. If protected against fire damage, it can even glide through lava. Its burrowing leaves behind no tunnel or hole, nor does it create any ripple or other sign of its presence. A move earth spell cast on an area containing the burrowing creature flings it back 30 feet, stunning it for 1 round unless it succeeds on a DC 15 Fortitude save.