Trailing Vine

The caster trains a thin, discreet vine onto the path made by the target NPC. The caster may use this to track the party's own movement, so that they can retrace their steps in a bewildering environment. The vine will grow quickly and follow the target at speeds up to 40 ft/round.

To track an NPC, the target cannot be aware that this spell has been cast on them. If the target notices the vine after the spell has been successfully cast, the vine will continue to follow regardless. The target cannot deceive or hide from the vine, but the vine cannot cross magical barriers, solid walls/doors, or chasms wider than 12 ft. The vine can climb walls and move through water. The the vine will lose the target if the target moves faster than 40 ft/round or takes flight. The vine can follow the target for up to 200 feet.  

After the vine follows the target as far as it can, it becomes a normal, non-magical vine with no special properties.    

At Level 9, the vine can move 60 ft/round, cross a 20 ft chasm, and is strong enough for a tiny creature to traverse.