Shadowy Apparitions have now been updated.Shadowy Apparition:
How do these work? Also, can they be damaged? Avoided? Do they eventually despawn, or are they like a bolt that has been launched, eventually going to hit the target? Do they have a minimum range, or target things not in combat?
--Currently they target -your- target (if hostile), regardless of who they spawned from (regarding Shadow Word: Pain's ticks), so you can trail multiples of this onto one target. Visual NYI. Spawning while moving seems to be intended as a way to continue damage, when you are unable to during mobile fights. However, they do not change targets upon target death (but this also helps with Hunters Feigning Death, or Shaman Reincarnating)
--Clarification is required for the other questions
While before they were basically a slow proc of Timbal's Focusing Crystal, at the moment they proc an actual copy of your character, like a Shadowform Mirror Image. This copy is a Guardian with 5 health. So far I have only been testing it on mobs, so I am not sure if they can be targeted and killed by other players, but I'll update this when I have had a chance to check. They cannot be "avoided" as they will always walk towards their target. They have also been fixed to proc and move towards the target that the SW: P was on, instead of your current target.
The change to a Guardian means that if the target they are walking towards dies before they reach them, the Apparition will walk back over to you and attack another of your targets instead of just being wasted. I have not seen them simply despawn, if there are no mobs left for them to attack they will simply follow you until you attack something else.