Using a third party tool that allows you to see latent, otherwise untargetable NPC. As it pertains to this, the Daily Reward System introduced several NPC into the game that when targeted in this way and killed dropped several rare items, such as Pandemonium Key, Novio Earring, Sea/Sky triggers, etc.
It's already patched though, plus they WILL be banning people related to this and track all items down from mules/alt accounts... you wouldn't have gotten away with it lol....