They appear as humanoid figures that are draped in tattered shrounds that grow longer the more potent the Wraith is.
Wraith travel in swarms and flocks and will attack anything within the Shadowlands that has a life spark. They are constantly hungry for energy and will drain the life force of a living being with their touch.
A younger, weaker wraith might take a few moments of touch to completely drain the average person. An elder wraith could drain and drop a person in their tracks with a single touch.
A common tactic to avoid wraiths is to plant a magical 'thumper' or heart in one location while you work in another so that they are drawn away from where you are doing whatever it is that brought you to the Shadowlands.
Wraith and Ghosts alike will attempt to feed from the magical 'spark' of the spell and can be kept busy for a while but not forever.The magical 'heart' appears as a large glowing ball of energy that will attrack wraiths and ghosts alike for miles.
The spell mimics the life-spark of a living being and will pulse, sending out wave after wave of light-energy as though it were a heart beating steadily. Though ghosts would not be able to drain much energy from it, wraiths will swarm around it in a large spiral column to pull energy from the spell until it's exhausted.