Also created those on nightmare fuel, guys. If that is inappropriate, walk away now.
Land Slime
This colossal slime grows unnoticed, creeping outwards in all directions in the land under the Green Hell, digging out small veins under the land. At any given time, there's not enough Land Slime anywhere to be a hazard. However, when the Land Slime senses prey, it slowly gathers itself around it, using its channels to transport slime from afar...
At first there is no way to tell if you have its attention. But slowly, as more slime builds up, the earth starts bulging. When there is almost enough slime, the earth has moving, shifting mounds in it. And at some point, seemingly random an unmeasurably large mass of slime bursts from the ground and attempts to wash over its prey.
The thing about Land Slime is that it's not just a hunter: it's magical, and its nature is the antithesis of teleportation spells, being sensitive and reactive to them. Attempting to teleport out of its grasp only kills a truckload of slime and buys some time, but more will come to take its place. This characteristic is what keeps the Land Slime in check, too- it cannot spread past Deeper Felarya for it is an unstable zone, and it cannot thrive in them.
Magenta Bound
The Magenta Bound is a strange mold, magenta with purple stains, and a bubbly texture. It grows as man-sized patches on the bark of trees all around the Green Hell, drawing nutrients from it most of the time.
When it senses something nearby, the Magenta Bound performs a strange movement- it separates itself from its tree, and leaps towards its target. If it makes contact, it releases a powerful toxin, killing it within minutes unless something is done. If it doesn't... it keeps rebounding, powerfully, trying to steer for its target for a minute or so.
A Magenta Bound that has caught a target starts digesting as soon as the target dies- and as it digests, it becomes soft, squishy, semitransparent, and traps bubbles of gas in its structure, becoming a buoyant spore deliverer, spreading spores throughout the Green Hell. Some creatures consider the spore form a delicacy... through the rotting corpse visible inside a bubble is not for the faint of heart.