-Wild:
the slime-mold is found is moist environments, whether that's swamps, caves, damp-forests, etc.
These creatures are mostly stationary. But over time they can engulf a 30-feet diameter if left untreated.
When any lifeform steps on one of the slime's tendrils it has formed, it will give the creature a 5-second warning, before the tendrils will start to wrap around the entity and consume them.
The entity is entirely engulfed in the molds tendrils, and melting away of their armor and flesh.
Once killed, there's nothing but skeletal remains of where the creature last was, acting as a No-Man's-Land for anyone and everything to be warned.
While any creature or weapon that isn't a firearm would work on the alien-like monster. It has acidic blood akin to arthropleura.
The most effective way to dispatch slime-mold's is either a heat or a charge-lantern.
Slime-Mold's do NOT like heat, so any form of flames will do, including torches on tames. But as for charge? The charge-lantern is over stimulating the creature, akin to electrocution.
If killed, the creature can be harvested for Mold.
Mold can be cooked and dried out to give something akin to blue-cheese. This food item gives more hunger then cooked-steak does, but the main use is to suto-wyvern milk.
Due to the molds high resilience, the consumer can gain hypo and hyperthermic insulation for half of the time wyvern-milk gives.
-Domesticated:
To tame a slime-mold, you'll need to cut off a sample from the core of the slime-mold.
Any sharp weapon will do, but once you cut off a slice, be warned. The slime-mold will not take kindly to that and will spread in a 10-feet radius almost instantly to engulf you.
Once you get out of that sticky situation, you'll need to cultivate your now severed slime-mold in a petri-dish.
You'll need to feed the mold to allow it to grow over time.
Once large enough to stay out of a petri-dish, you can now place it where ever you want, and allow it to fully grow.
Once fully grown, it'll start to spread its tendrils where ever it is.
It can still be moved, but it'll have to restart it's spreading.
The usage of a tamed slime-mold is to act as either a alarm-system, tied to your phone for all of the PvP players. But the main use of them, is to be used as traps.
The tendrils of it will engulf any sized creature, from compy sized to giga sized.
Tamed slime-mold's have settings akin to Plant-X's, but instead of 'kill or not kill' it's 'kill or keep trapped'
The slime-mold will keep the creature still until it either breaks loose, or someone knocks out the creature. If it's a flier, they can grab the flier out of the sky if it's low enough, and force it to land.
This could be used to even help for Reaper-Queen impregnation. Making the Queen stay stationary while impregnating players. Akin to player-made traps.
Only downside is, a creature as large as Giga's or the Carchar don't immobilize it, but slows it down. Making it still hard to trap the ARK's highest existing apex-predators.