Thanks! And those are the "phantoms", as eluded to in the tutorial/description. They can't hurt your house but you can't be certain if an enemy is real or a phantom until you shoot it, hence the 'don't trust your eyes'. Lore wise it's spillage from other dimensions because of all the inter dimensional travel. We went pretty hard on the "Show don't tell" part of those but it might have been a bit too unclear :)