- Crystallized Husks, a slightly tougher variant of the Husk Miners with a laser attack, are only fought in the uppermost passage of Crystal Peak leading to Hallownest's Crown.
- The Mantis Traitors in the Traitor Lord's room do not drop Geo.
- Carver Hatchers are only found in the Failed Tramway section of Deepnest.
- Lesser Mawleks, a mook counterpart to the Brooding Mawlek boss, only appear in one segment of the Ancient Basin, and the player will only fight three or four at most to retrieve the chunk of Pale Ore from said area.
- The Brooding Mawlek encountered in the Colosseum of Fools is smaller and thinner than the one encountered in the Forgotten Crossroads. This is purely cosmetic and does not affect much on its mechanics.
- The Volt Twister, an Underground Monkey variant of the Soul Twister with a lightning attack similar to the boss Uumuu, only appears in the tenth and seventeenth waves of the Trial of the Fools, for a total of four individuals.
- Only two Alubas (dragonfly-like bugs) appear in the game, one at the Lake of Unn, the other outside the White Lady's den. They don't attack, and exist solely to fill out the Hunter's Journal.
- The path to the Sharp Shadow charm has a short variant of the Garpede not seen elsewhere.
- Mossy Vagabonds are only found in a Disconnected Side Area of the Queen's Gardens accessible from the Fungal Wastes, accompanying the Moss Prophet. If you didn't discover their hideout before defeating the Broken Vessel, they'll all be dead from the Infection, though you can still inspect their corpses for the Monster Compendium entry.
- The Gorgeous Husk is a unique gold-plated Husk found in a well-hidden room at the City Of Tears' east end. It has higher HP than other Husk variants, but is not tough enough to qualify as a boss or miniboss. It's also a Piñata Enemy, since it drops 420 Geo upon death, the highest amount that a single mook drops in the game.
- Weavers were planned to be regular encounters in Deepnest, but only one appears in the final game, in the hidden Weaver's Den.
- The Husk Guard is only encountered alive in two instances, both in Forgotten Crossroads, one of which stops respawning after the area becomes infected, although corpses of them are seen in Fog Canyon.
- The two Husk Warriors in the hallway above the Crossroads Stag Station are the only appearance of their kind.
- Infected Myla shares the attacks and appearance of a Husk Miner, though she has unique lines when hit with the Dream Nail, as well as a unique death cry. She also does not respawn upon being slain.
- There is a lone Moss Knight standing at the ledge near the Lake of Unn. It only attacks the Knight once you provoke it, it has a unique Dream Nail dialogue ("...She is calling... Home so close..."), and doesn't respawn once killed.
- The Menderbug crosses this trope with Metal Slime, since he could only spawn at a 2% chance if you break the sign at the entrance of the Forgotten Crossroads below Dirtmouth and re-enter. He will notice the Knight and quickly fly away. Since he is fast and the Knight is momentarily motionless from taking the fall, the only way to damage and kill the Menderbug is to use the Desolate Dive/Descending Dark. Doing so will unlock the door to his house and read his diary.
- Although not technically a boss, the Pale Lurker's fight locks you in the room, requiring you to defeat her in order to exit. She only flees from you and leaves traps behind to slow you down, but she doesn't have a large amount of health comparable to bosses. She also has a Mighty Roar intro, but without the Boss Subtitles. Her death animation is also fast, like a typical mook. Lastly, the Pale Lurker is one of the few enemies in the game that are scripted to drop an item upon death. Alas, there's only one of her in the secret area of the Colosseum of Fools.
Unique Enemy / Hollow Knight