In SpaceBlock, Water Breathing potions come up as Artless Potions in auction. I don't know if that's server wide or not. If it's extended, it comes up as Artless Potion (ext).
According to this: http://www.minecraftforum.net/forum...ival-mode/282040-secret-potions-with-item-ids It's part of minecraft itself, sort of like a hidden easter egg, it could be that the plugin just hasn't been setup to read the new potion so it's using the name Artless since it's part of the game.
