I designed this a couple years ago and I've alway loved it. I'm not exactly sure if it would qualify as a Wondrous Item, but here it is.
Stuck Arrow (Bolt): This is a solid iron arrow or bolt that upon impact will act as an Immovable Rod. The arrow/bolt will not move from where it is, even if staying in place defies gravity. This enchantment will last for 60 minutes, at which point, it becomes a non-magical item. The arrow/bolt can support up to 2,000 pounds before falling to the ground. If a creature pushes against it, it must make a DC 25 Strength check to move the arrow/bolt up to 10 feet in a single round.
If the arrow/bolt has dealt any damage to a target any attempted movement deals an additional 2d6 damage. This movement requires a full round action and requires a DC15 strength check to allow the victim to tear free. This allows for a 5-foot movement. A failing check prevents the victim from tearing free. A stuck target does not get any Dex bonus.
This arrow will deal double damage + 2d6 against any charging opponent. The target must then make a DC 30 Strength check or the charge is broken.
Any player making a mounted charge who fails the strength check, or who's mount is hit, must make a DC 30 ride check or be removed from their mount. Any creature suspended in the air by a wound from a stuck arrow, whether in this fashion or not, automatically takes an extra 2d6 subdual pain damage every round they remain suspended. A creature so suspended that is incapable of flight takes a -2 penalty on the strength check to move after being struck.
"I find targets so much easier to hit once they stop moving". William Tell
Moderate transmutation; CL 10th; Craft Magic Arms and Armor, levitate; Price 500 gp.