Energy Drain

       Usage: cast 'energy drain' <target> : cast 25 <target>
      Damage: 1d20 usually (See below)
        Save: Save vs. Magic
        Cost: 24
    Duration: Instant
Casting Time: 12
      Target: One MOB or character

On opponents at around the same level or higher as the caster, this spell does
1d20 as shown above.  If the spell is used on an opponent less than one-third
of the caster's level, then the spell does damage equal to one-third of the
opponents max hp, assuming this is greater than 1d20.  If the spell is used
on an opponent between one-third and two-thirds of the caster's level, then it
does one-sixth of the opponents max hp, assuming this is greater than 1d20.

The classes that get the spell energy drain are:

necromancer: Level  72 (excellent)