Q 169

Is there any indication that undead are always supposed to be immune to hp damage from negative energy, or that they're always supposed to be healed rather than harmed by it? The SRD only says "Negative energy (such as an inflict spell) can heal undead creatures", not that it necessarily does -- and the mechanics of chill touch would certainly seem to suggest it's not always the case.

At a glance, black sand and the dark tide spell appear to harm undead exactly as they do living creatures.