(covers information from several alternate timelines)
A monster, or beast, was a legendary creature that inspired fear or horror. Often, these fictional creatures turned out to be based on some scientific truth.
In some cases, a first encounter with an alien could cause a fear of monsters. (Star Trek: First Contact)
Many worlds had creatures that resembled Earth's sea monsters. (TAS: "The Ambergris Element"; VOY: "Thirty Days")
On Earth, during the holiday of Halloween, people often dressed as various monsters. (TOS: "Catspaw")
The Bajoran people saw the Cardassians as monsters, something with which Tekeny Ghemor agreed. (DS9: "Ties of Blood and Water")
Charles Tucker III was a fan of "monster movies." Hoshi Sato therefore guessed The Andromeda Strain was about a "Doctor Andromeda" who built a monster, which killed him in the end. (ENT: "Observer Effect")
Doctor Kila Marr called the Crystalline Entity that was responsible for her son's death a "monster". (TNG: "Silicon Avatar")
After Jake Sisko saw his father, Benjamin, return to normal time, explaining it to Jadzia Dax made him feel "like a child insisting his parents check under his bed for monsters." (DS9: "The Visitor")
Julian Bashir once claimed that the word "monster" was "acceptable" in describing genetically engineered people. (DS9: "Doctor Bashir, I Presume")
Dukat was called a "monster" by several people, something he thought was unfair. (DS9: "Waltz", "Wrongs Darker Than Death or Night")
Kes called the Ilari Tieran a "monster" while fighting his mind inside herself. (VOY: "Warlord")
Neelix helped Naomi Wildman get to sleep by searching the quarters for monsters, even such places as the replicator. (VOY: "Mortal Coil")
Sometime before 2375, Tom Paris had a monster movie marathon. He promised to pay Neelix double with next month's replicator rations for allowing him to make pork rinds. The Talaxian reminded Paris of this when he begged Neelix to provide him a romantic dinner for the anniversary of his and B'Elanna Torres' first date. (VOY: "Warhead")
A related word to "monster" was "monstrosity", denoting an object that was either overly large and/or hideous. Upon his first sight of Starbase Yorktown in 2263 of the alternate reality, Doctor Leonard McCoy called that starbase "a damn monstrosity." (Star Trek Beyond)
Monsters
By cultural origin
Human
- Banshee
- Devil
- Dragon
- Frankenstein's monster
- Gill-man
- Gremlins
- Grendel
- Grover
- Loch Ness monster
- Vampire (Human; see Salt vampire, vampire bat, Vampire Vixens)
- Werewolf
- Witch
- Zombie
- An unspecified Mutant lizard
Klingon
Other
- Ardra (Ventaxian)
- Morrok (Drayan)
- Vihaar (Malon)
- Ghost (Various)
- Trevis (aka the Tree Monster, from Flotter and the Tree Monster)
Monsters in fiction
Books
Movies
- Attack of the Lobster People
- Bride of the Corpse
- Frankenstein
- Night of the Killer Androids
- Orgy of the Walking Dead
- Revenge of the Creature