- Type: Ghost/Psychic
- Species: Masked Nightmare Fakemon
- Ability: Fright (lowers foe's Special Attack when the user enters the battle)
- Hidden Ability: Bad Dreams (sleeping opponents take damage over time)
- Height: 4'6"/1.4m
- Weight: 84lb/38.1kg
- Body Style: Head and base
- Gender Ratio: 1M/1F
- Physiology: Horrnors' bodies consist of a coiled, spiraling system of pipes. A lighter-colored set of limb-like pipes are thought to be the remnants of their arms. Several darker blue spots can be found on its body. Its "tail" is spike-like. Its neck sharply angles towards its bell-shaped head. Its true face is a mystery, as it is always obscured by blue fog. If anyone were to see it, they would faint from shock.
A Horrnor's large mask is its distinctive feature. It is navy blue and shield-shaped, and levitates in front of its true face. Six blue eyes are arranged in the six-spoked asterisk pattern characterisic of the Trembone line. However, these eyes are merely for show. Its face appears to be screaming. Floating above its mask is an accent (>) mark. Its mask radiates with several thick tendrils. On its body is three tendrils, usually only on one side.
- Gender Differences: The symbol above a female's mask is reversed (<) .
- Special Abilities: Horrnor are very intelligent, and are said to love music. They are excellent at manipulating other Trembone and Trumpmare, as a sort of "alpha male" (although female Horrnor are just as skilled). Its psychic powers are powerful enough to summon incredible blasts of psychic power to attack with. Compared to their pre-evolution, they are much slower yet more durable and powerful.
- Behavior: Horrnor are very controlling of others, and have high dominance- a struggle for trainers to deal with. They also seem to be attracted to music, given their design. They can use telepathy to speak.
- Habitat: Horrnor inhabit plains.
- Fakedex Entry 1: Its mask hides a face that is said to be so horrifying it causes anyone that sees it to faint.
- Fakedex Entry 2: An incredibly powerful and intelligent Fakemon, it is dominant over Trembone and Trumpmare, as well as its trainers. Some say it likes music.
- Fakedex Entry 3: It can detect even the slightest change in sound or rhythm, making it very good at music.
- HP: 80
- Attack: 40
- Defense: 80
- Sp. Attack: 130
- Sp. Defense: 100
- Speed: 80
- Total: 510
- EV Yield: 3 STK
- Evolution: Horrnor evolves from Trumpmare when traded, which evolves from Trembone at level 25.
- Name Origins: "Horror" + "Horn"
- Physical Origins: Horrnor's body is based on a French Horn. Its face has origins in the "mascot" of the band Shpongle, which is a six-eyed floating blue head.
- Shiny color: Dull yellow