Pass Without Trace

Player's Handbook v.3.5 (PH)Core (3.5)
School
Transmutation
Casting Time
1 standard action
Components
V, S, DF
Range
Touch
Target
One creature/caster level
Duration
1 hour/level (D)
Saving Throw
Will negates (harmless)
Spell Resistance
Yes (harmless)

The subject or subjects can move through any type of terrain—mud, snow, dust, or the like—and leave neither footprints nor scent. Tracking the subjects is impossible by nonmagical means.