I'm not sure if this is a shill bidder, but there is definitely something weird going on.
Check out this item:
http://www.ebay.com/itm/1984-KENNER-STAR-WARS-YOUNG-JEDI-KNIGHT-MAIL-AWAY-SET-MINT-COMPLETE-ULTRA-RARE-/311678105806
If you look at the 27 bids, the bidder k****2 was the second...