mine does the same thing, just noticed it last night btw.
quote from wowhead,
"This appears to be a non-combat NPC used in Northrend for the targeting of other NPC's non-combat abilities.
Example: The Surge Needle Sorcerer in Dragonblight will target this to cast their large arc of purple magical energy at a single location nonstop while not in combat. It gives it that effect of "charging something up".
Other examples include the Scavenge-bot 004-A8 in Borean Tundra to use their Cutting Lazer ability on the pipes in the area while not in combat."