freyar
Extradimensional Explorer
Heh, or positive levels from undead. Do you want to leave in the idea that it can't affect lawful critters? Seems a bit biased, though I guess it makes sense if goatlings are themselves lawful (or good). Anyway, here's a draft without it.
Discerp (Su): X times per day, a goatling can drain energy from magical creatures, including undead, dragons, and outsiders. The victim must be physically or magically restrained in some way. The victim must make a DC X Will save or gain a negative level (positive level in the case of undead), and the goatling gains 10 empowerment points. If the victim has as many negative levels as HD, it falls unconscious rather than dying. Negative levels are recovered at the rate of 1/day and never become permanent.
Discerp (Su): X times per day, a goatling can drain energy from magical creatures, including undead, dragons, and outsiders. The victim must be physically or magically restrained in some way. The victim must make a DC X Will save or gain a negative level (positive level in the case of undead), and the goatling gains 10 empowerment points. If the victim has as many negative levels as HD, it falls unconscious rather than dying. Negative levels are recovered at the rate of 1/day and never become permanent.