Power Sight

(Masters of the Wild: A Guidebook to Barbarians, Druids, and Rangers, page 92, DnD 3.0)

Divination

Level: ; Druid 1
Components: V, S
Casting Time: 1 action
Range: Close (25 ft. + 5ft./2 levels)
Target: One creature
Effect: Instantaneous
Saving Throw: None
Spell Resistance: No

You determine the number of Hit Dice (including those from class levels) a creature currently has. If the creature has both monster Hit Dice and class levels, power sight reveals only the total. You cannot determine what class levels a creature has, and negative levels do not count against its HD. For example, both a 10-HD creature and a 10th-level character with 4 negative levels appear as 10-HD creatures.