The Spectral Knight, also known as Sir X-Ray, is the first boss encountered in the Nintendo 3DS Streetpass Mii Plaza game Monster Manor. His weakness is WIND (green). As the name suggests, it is a hostile ghost in the form of a luminous knight on horseback, armed with a large lance that it uses to stab and skewer the player. The Spectral Knight often attempts to form a ghostly defense to temporarily shield itself from counterattacks, though the player can still successfully damage it before it does this.
The Spectral Knight is fought on Floors 5, 20 and 35, and its health and attacks increase dramatically with each battle. The Spectral Knight is vulnerable to wind weapons, though like all other enemies, it will take damage from any weapon that is used against it. After defeating the Spectral Knight on the fifth floor, the player receives a Plaza Ticket.