Adding a little unexpected to your magic bag of critters or the like.

Where came the sickness, the shaman knew not. No herb, no smoke, no spirit dance could carry it away. What curse of heaven carried the plague, the sages and priests could not say. The gods struck, and no prayer, no elixir could save their victims. How the malaise spread, no doctor could know. With not even a body to spread the miasma, surely it must be a curse. And when at last, the right lenses were turned upon the pus of the suffering.  

The Usagin is a high end biomod that is a popular niche product in the Cosmic Era. The dedication required to become a bunnyperson is serious, as some of the mods are invasive and make some common tech devices no longer operational for the usagin.

A way to increase the danger of a monster through an unusual mechanic

An ancient race of nearly-humanoid spiders that have lived on the fringes of civilization for as long as recorded history.

Gijinkagrams are a niche anomaly in the Cosmic Era, and they can be eliminated by routine maintenance on high end electronic systems. 

"AAAAAAHH, it's a troll!"
"Protect the women and children! Grab your torches!"

"AAAAAAHH, it's a troll!"
"****head... we banned him five times and he keeps making new accounts about how he pwns all and that he>>>>>>>>>>>>>>>>>>>j00!"

The most common domestic companion animal of the Kel'Regar, the Kel'Mestath has been bred into a wide variety of sizes and roles. Humans and their allied species often think of them as similar to cats or dogs, a perspective that the Kel usually encourage, for the full understanding of the Mestath tends to cause a certain level of discomfort in many aliens, but especially that close ally, humans.

An ethereal/astral parasite that feeds on emotion

also known as a great goblin, dread goblin, or super goblin

A highly transient form of digital life

A slowly growing bomb in the CogNet

A golem that packs a surprise!

The Karkos represent an attempt to create a bad guy race with almost no redeeming features, a true villainous species without resorting to established tropes or handwaving.

An Abnegator is a synth or augmented human who has had the misfortune of being fitted with an emotion radiator

A delicacy unique to the Tarkis Desert.

Or Bearshrews if you prefer. The debate rages on among naturalists. Both names are used interchangeably for these creatures.

Seriously - why hasn't one or another Artificial Intelligence simply taken over? In any setting that is in a close or more distant future, the possibility of a machine that is able to learn and grow without biological restraints brings up the question.

Inspired by Carrion Crawlers, Gelatinous Cube , Owl  Bear and the Stirge

"You see, there was this contest ......"

A bit of fluff for your game