You searched for TRUE SIGHT DETECT INVIS DETECTS
1. true sight detect invis detects
Syntax: cast 'true sight' (<target>)
With the true sight effect, you can see characters which are invisible. You
will also be notified of negative healing rates in rooms. To those not
affected by true sight, yukes standing in the dark appear as silent souls,
shadows appear as shadowy figures, players affected by the disguise spell
appear as such, and blurred players appear as blurry figures.
This spell does not aid in detecting duo dimensioned players.