A plugin for TShock that allows admins to become invisible to their players.
What is actually happening though, is far more complicated. This kind of invisibilty requires no buffs, and is undetectable by people with modded clients (mostly). You can also chat, use commands, whisper people, and you won't appear on the player list all at the same time while using this plugin. It is toggleable by using the "/ghost" command and having the "ghost.ghost" permission.