Duplighosts are ghost-like creatures that can take on the appearance, voice and abilities of other people. They first appeared in Paper Mario, and a single Duplighost was later featured in the sequel, Paper Mario: The Thousand-Year Door. To attack, Duplighosts can either fly into Mario, or turn into his partner. In partner form, a Duplighost's attacks are weaker, and changing takes up a move, giving Mario a better chance at winning the battle. "Duplighost" is word play on "duplicate", one of their moves.
A Duplighosts was first seen in Paper Mario at the Toad Town Dojo, where Mario fought a blue-sheeted Duplighost named Lee. More Duplighosts appeared in Chapter 7, in the Crystal Palace, where they used the mirrors in the palace to confuse Mario, as the reflections make it tricky to determine whether a character is the real thing, or a Duplighost. Another Duplighost appears in Bowser's Keep, trying to trick Mario into believing he is Princess Peach. Mario can break the Duplighost's disguise by hammering the fake Princess repeatedly.
Paper Mario: The Thousand Year DoorEdit
Paper Mario: The Thousand-Year Door hints that Duplighosts may actually be a type of demon. Many Twilighters refer to Doopliss, that game's only Duplighost, as a demon haunting the Creepy Steeple.