Monsters are the primary antagonists of Among the Sleep and its untitled prologue DLC. The original game features three monsters, while the DLC features two; these sets are exclusive.
The monsters' appearances are filtered through the imagination of The Toddler. As such, their appearances are relatively abstract and yet also quite simple.
Upon detecting a monster's presence, The Toddler will panic, manifesting as distorted vision and disturbing audio. If they make contact, The Toddler suffers a Game Over and must continue from an earlier portion of the stage. However, monsters are capable of sneaking up quietly behind the Toddler without triggering any of these cues, so he should always be aware in all directions.
Original game Edit
The original game contains three monsters. All three of them represent The Mother, who is an alcoholic, at different stages of her drinking.
Harald EditHarald resembles a silhouette tall figure wearing a coat & boots, she also holding a parasol. She represents The Mother donning a trench coat and leaving the house at night to purchase wine.
It shortly appeared as a shadow in the corner of the living room right before a lightning bolt struck. Because of her temporary absence, no monster attacks the boy early in the game. However, a jump scare of the Stranger occurs as a scripted event within the house and it might be able to catch him in The Playground.
The Stranger is the only monster in the original game who doesn't show white glowing eyes.
Hyda EditHyda or the Forest Lady represents the boy's mother. It appears in the Hyda Forest and represents the Mother soon after drinking and while drunk; as symbolized by a transforming painting showing a woman gradually becoming the monster after drawing water from a well.
The Toddler likely received inspiration for this relatively artistic level from the book read early in the game featuring "five thirsty animals" digging a well for water. He would thus perceive wine as some kind of "bad water."
When the child enters the room with a fireplace, you see a hole with water where she slowly goes up then down. It is in the Forest level, that he first encounters significant volumes of wine bottles.
Heap EditHeap appears in the third level, The Closet, and represents The Mother while hungover, as indicated by its hatred of loud sounds.
Heap is special among the monsters in that, along with capturing the Toddler and causing a Game Over, it will also throw things at him.
In the final game sequence, just as he is about to escape, it grabs him by the foot and seizes Teddy, causing his arm to be torn off. He later exits the closet at daytime and finds the Mother sobbing with an empty bottle of wine in one hand and Teddy in the other.
It is implied in the introductory sequence that he frequently hides in the closet from the Mother, and it is shown after completing the Closet level, that it indeed takes place hiding in the actual closet. This may cause her attempts to seize him to appear like the various coats in the closet are attacking him, explaining why this monster resembles a trench coat and why all such coats among the house appear so imposing.
Prologue DLC Edit
The prologue DLC takes place in an unknown amount of time before the main game and features two monsters unique to itself.
The Silhouette Edit
While wandering the house, the Toddler must evade a shadowy silhouette vaguely similar to The Stranger from the previous game. Its precise behavior and symbolism are unknown; however, it likely represents The Mother in some way as she is the only one in the house and is known from the original game to be abusive.
The Boiler Edit
In the basement of the house is a large, retro-style boiler. Upon moving far enough into a dark spot in front of the Boiler, it will suddenly come alive, roaring and blazing, and chase after the boy with clumsy hops. If he then moves out of its activation zone and looks away, it will instantly return to its original space and wait to be awakened again.
In front of it are two light switches that can only be reached by climbing the nearby boxes. When he is within the light toggled by these switches, the Boiler returns to dormancy.
The Boiler can also be run straight past if he is quick enough. The reason for this is probably about how scary machines can be to other toddler.