Earth Glide

A creature with Earth Glide can tunnel through dirt, rock and other non-magical ground materials. Creatures with Earth Glide may choose each round whether they leave behind a tunnel, or the tunnel collapses behind them after 1 round.

A creature with earth glide must be able to trace line of effect to any creature it wishes to attack. Since line of effect is always bi-directional, a creature cannot use earth glide to make attacks while being immune to attacks itself.

Attacks of opportunity against creatures with burrowing rely on the attacking creature's ability to draw line of effect to the square the burrowing creature just left. That is, if the burrowing creature is on the surface, and burrows into the ground, leaving a threatened square, the attacker probably has line of effect and can therefore make an attack of opportunity. However, passing under a creature while burrowing probably does not provoke attacks of opportunity, as the would-be attacker probably can't draw line of effect into the ground (unless he also has a Burrow speed, for example).

Depending on the way they move through solid materials, Earth Glide may grant up to a +8 bonus on Might checks. An Adamantine Mole probably would, since it Earth Glides through prodigious strength, but a Subterran Gas might not.

• Prone: A creature with earth glide cannot be made Prone, but any time they are subject to the Prone condition, they are instead Slowed for one move action, after which it automatically clears (even if they don't move).

• Difficult Terrain: Earth glide generally allows a creature to bypass difficult terrain, since they can just go under or around it, even when passing through the ground at the surface which is deemed difficult terrain.

• Permitted Movement: A creature with Earth Glide can make charges, take 5-foot steps, run or withdraw while burrowing.

• Overland Travel: Outside of combat, creatures with Earth Glide travel overland at twice the pace of a walking creature with the same speed.