Sight Beyond Sight (3.5e Sacrifice)
From D&D Wiki
Clearing your mind, your spirit travels through your own gate... and through the gates of others, living or undead. Through this you gain knowledge of the unseen. You duplicate the effects of Clairaudience/Clairvoyance except that you may move the sensor after it is placed at a speed of 10 ft per round. However, the vision is not normal, you see through a form of life-sight. Living creatures in the area shed light as a torch up to 100 ft, while undead creatures shed light out to 50 ft. If there are no living creatures, or there are solid objects blocking the light, you are otherwise blind of your surroundings.
Health Cost: -5.