One of the facts about reality that I find weirdest is that 1) homo sapiens sapiens are the only members of the homo genus, and 2) this has only been true for a relatively short amount of time.
Also, despite being pretty gung ho about Star Trek forehead ridge aliens or elves/dwarves/etc., the idea of seeing something that looks human but isn't triggers my fight or flight response. I get upset.
In that spirit, here are two upsetting creatures to place into your games. Natural philosophers characterize them as being human-adjacent, but in no way are they homo sapiens. This is because they are not sapient.
|From The Sword of Glass by Sylviane Corgiat|
Gigas are quadrupedal non-sapient humanoids. They run sorta like people who participate in pony play. They cannot easily stand on their back legs so you measure them to their shoulder. On average, they reach about 19 hands high.
Despite their size, gigas are quite skittish. They flee from most perceived threats, although the males can be territorial during mating season. When threatened, they can be enormously dangerous. They have muscle mass like an orangutan. Their bite carries poisonous bacteria.
Gigas are herbivorous and subsist mostly on grasses. Herds of gigas roam in temperate plains biomes.
Gigas have been domesticated by gnolls, who train them to act as warhorses.
|From Basileus by Andrew Whyte|
Nginikin are non-sapient humanoids the size of action figures. They fill the same ecological niche as rats. They infest ships and are inadvertently introduced to new ecologies, which they proceed to devastate. Everybody hates them.
Nginikin are omnivorous. Like goats, they can eat almost everything. They reproduce extraordinarily quickly and are frequently seen as symbols of fertility. As such, they are the primary ingredients for a variety of aphrodisiacs and fertility potions.
Most upsettingly, they have the capacity for mimicry. Though about as intelligent as rabbits, they can recreate the sounds of human language. Many people are tortured by the squeaks of "Howre uu dooin" coming from their crawlspaces.