I've seen Dusknoir paired with Landorus-EX recently. That's personally not my cup of tea but I can certainly see why someone would want to run it. HAmmerhead can stick damage on benched Pokemon, which you can manipulate around later. I've even seen Diusnkoir used in a few Yveltal varients, since there's often overkill damage that you can save for future KOs.
On a side note, Meowstic FLF can perform the same effect via its attack, Ear Influence. This is an intereating alternative to Dusknoir in a format where Garbodor sees a lot of play. Meowstic needs a (P) energy to do its thing, but it's a Stage 1, so less space in your deck and easier to get out. It does take up your attack for the turn, but since it's an attack rather than Ability, Garbodor doesn't stop it.