This is designed to test magicians who's perceptions you're not sure of.
Draw a sigil on a piece of paper to represent your servitor, this sigil should have some open space in the center so that you may draw a sigil to represent another magician who is known to your target.
Charge the sigil, while focussing on the image of a ball of energy spilling over fire and sloppiness. Charge the ball so it is large and clumsy. Give it no cloaking capabilities. Program it to be noticable by people with moderate sensitivity. Program it to follow your target and come in contact with your target causing nothing to happen to the target, but attempting to throw itself into the target's awareness. The energy you use should be unrefined,
easily readable, but not connected to you. It should be able to maintain a form, but not something which will threaten the target. Just enough that it's noticable and mentionable. Program the servitor to project a suggestion of discussing the observation in detail with other magicians. Give it the ability to effect dreams, visionary states, and the like. Program it to force itself on the person enough to be noticable, but not enough to provoke
amazing concentration, or enough to make someone without the ability to percieve magic detect it.
When you're finished the base programing, draw a sigil to represent another magician known to your target within the sigil of the servitor. Focus on that magician and his energy signature while drawing the sigil, Bend the servitor so that it projects the other magician's magical fingerprint and not yours.
Send the servitor out to haunt the individual whom you're testing.