A creature with this feat (from Races of Stone) is, with some effort, able to sense other creatures in touch with the earth.
Prerequisites: Con 13, Wis 13
Prohibited: Creatures with the [air] or [aquatic] subtype cannot select this feat.
Benefit: As long as you are touching the ground, you can take a move action to sense the number of creatures also touching the ground within 20 ft. of you, and the direction to each of those creatures. The detection is not precise enough to pinpoint the location of any creature.