Detect undead

Detect undead was a divination or necromancy spell that revealed undead creatures within a certain distance from the caster. The earliest version of this spell could be cast in reverse as cloak undead.

Effects
This spell evolved over time. The earliest version operated in a sphere centered on the caster of radius equal to 10 ft (3 m) times the experience level of the caster and it revealed the location of even invisible or concealed undead. A prickling sensation warned the caster if any undead entered the area during the few minutes of the spell's duration. The next version of detect undead had a much greater range (60 ft/18.3 m plus 10 ft/3 m per level of the caster) and duration (30 minutes) but only worked in a corridor 10 ft (3 m) wide, forcing the caster to turn about in order to sweep out the entire surrounding area. This version only gave direction to the undead, not location or distance, and it could be blocked by 1 ft (30 cm) of solid stone, 3 ft (0.9 m) of wood or dirt, or a thin sheet of metal.

The next version of this spell was limited to a range of 60 ft (18.3 m) but worked in a cone-shaped field of view and was much more sensitive. More information could be obtained by remaining motionless and concentrating on the area. At first, only the presence or absence of undead could be detected. After a few more seconds of concentration the number of undead auras and the strength (either faint, moderate, strong, or overwhelming) of the strongest aura could be determined. At this point, if a particularly powerful undead was present and its aura overwhelmed a good-aligned caster then the caster became stunned for a few seconds and the detect undead spell was broken. If the caster was able to continue concentrating on the area, then at last the location and strength of each aura could be discerned. If an object or wall blocked the line of sight, then direction was apparent but not distance. This spell was sensitive enough to detect lingering auras left behind after an undead creature was destroyed. The weakest undead left an aura only dimly detectable for a few seconds to a few minutes, possibly an hour. The destruction of a powerful undead creature could still be dimly detected by this version of the spell for a few days afterward. Similar to its predecessor, this spell could be blocked by 1 ft (30 cm) of solid stone, 3 ft (0.9 m) of wood or dirt, 1 in (2.5 cm) of common metal, or a thin sheet of lead.

Components
The earliest version of detect undead required only verbal and somatic components. Later versions needed a sample of dirt from a grave as a material component. The divine magic version used the caster's holy symbol or divine focus instead of grave dirt.