Arcane Jelly

Stumbling through brash and bracken, sky blue robes torn and tattered, the magician runs. Around him, the forest is dark and unforgiving. Tendrils and branches and brambles reach down through the dense tree cover to rake his face, drawing lines in thin red ink from thorny quills. The light suede of his shoes is now rich brown with thick mud and festooned with dead needles form the ancient hemlocks, contorting and forming dark coils around him. Their bark is spongy, warped and hollow, as if the trees could draw anyone foolish to reach in inside. No bird calls. No creature scampers from tree to tree. The only sounds in the wood are the panting of the wizard, his footsteps, and the steady hum of the wind through the trees paired with the creaking, the groaning of the twisting trunks. A clearing. A pond choked in algae and slime. A mound of boulders, wet with thick moss. A little cairn. He stops to catch his breath. A bubble surfaces in the pond. It bursts, scattering algae over the surface, which ripples and shivers. The hemlocks moan in the wind, and the pond's algae swirls. The forest sounds are joined, now, by a low gurgle. He looks up, steps back, more bubbles surface, the gurgle grows to a growl, his hands wrap around his staff, and now a low roar. He raises his staff to the pond, and then a sudden gust of wind, and the moss on the boulder animates, leaps at the magician, he stumbles back, toppling the cairn, casts a spell which is absorbed by the moss' shapeless form, and he is then no more. All that is left is the toppled cairn, and the mud-caked staff abandoned on the ground.
Arcane jellies are shapeless ambush predators which live solitary lives, mainly in swamps. Their main feature is their absorption of magic to fuel their own magical abilities, which is why, although they most often hunt small animals, they will take risks to hunt magic users and will make use of their unique magical abilities, such as limited teleportation, to give chase to more valuable prey. An arcane jelly in it's true form looks like a lime green jelly, which sometimes crackles with arcane energy. It's illusion magic, however, allows it to change it's appearance into other shapeless natural forms, such as moss, clay or algae.
Although it's main diet consists of small game, and your classic apex predator might try to attack larger prey, an arcane jelly is classified as apex because no one wants to eat magic, acidic slime.

Magical Ability

Arcane jellies have a store of magic in their bodies, which they use for a multitude of purposes. First and foremost, the ooze has no eyes or other sensory organs, so they keep an emergency reserve of magical energy to maintain their senses. The second most important use of their magic is teleportation. Being an ooze, an arcane jelly has very little mobility. Teleportation allows the jelly to gain greater mobility when tracking or fleeing intelligent foes. The third most important use of their magic is their illusory disguises, which allow them to lure in their prey. This is not as important as the two uses mentioned above, as the arcane jelly, although it benefits more from ingesting prey, it is omnivorous, and can digest plant matter. Arcane jellies can also focus their magic into evocation if attacked by a more powerful foe.

Basic Information

Genetics and Reproduction

The arcane jelly reproduces asexually. When a jelly gains enough mass, and it's magical energy is at a sufficient level, the arcane jelly will split into two jellies. The two jellies will either flee each-other, or attack each-other. If they attack, they will likely reform into the original jelly, which will then again split in a short time.

Dietary Needs and Habits

An arcane jelly is omnivorous. To sustain itself, it prefers to eat small game animals, and will occasionally attack larger prey, such as deer. However their acidic body can digest any organic matter. Matter alone is not enough to sustain them, however. Arcane jellies rely on magic for their senses and abilities, so it is essential that they occasionally target magic users. To get the most out of a magic user, an arcane jelly will (unless the mage is too powerful for the ooze - very potent magic can overload a jelly's system) ambush the mage when it is close enough, but will not move in for the kill. Instead, it will stall for long enough for the magician to attack it with spells, which it will absorb to replenish it's magic.

Additional Information

Perception and Sensory Capabilities

Arcane jellies rely on magic for their sensory input, and have gained sophisticated smell, hearing and sight, with the aid of magic. They also have the ability to 'smell' magic, to lead them to their favoured prey - magic using humanoids. This sense also allows them to detect the power of the magic, allowing them to avoid magic users who's abilities might overload the magic in the ooze.

Intelligence

An arcane jelly is vastly more intelligent than other oozes, by virtue of mutations brought about by magic absorption, and the requirement to hunt sentient prey. This allows it to make use of it's magical abilities and use more advanced hunting techniques, such as feinting to lure spell-casters to attack it with magic for it to absorb.

Habitat

Arcane Jellies live primarily in swamps, bogs, marshes and underground in caves and dungeons.

Arcane Elder Oozes

Very rarely, an arcane jelly will lack the ability to split when it reaches sufficient mass. Such a jelly can accumulate a colossal amount of magic and mass, becoming an arcane elder ooze. A lesser kind of arcane elder ooze also exists, a magic starved arcane elder ooze, which forms when an arcane jelly accumulates a huge amount of mass, but does not have enough magic to split. When struck by a powerful spell, such an ooze can explode into a swarm of tiny arcane jellies, flooding the opponents.

Uses for Humanoids

WARNING: Do not attempt to domesticate an Arcane Jelly. It's a humanoid-eating monstrosity, who's sole purpose is to eat as much as possible, including you. Don't even try.

Guard Creatures

Arcane jellies are prizes as guard creatures to defend against spellcasters, and can sometimes (although it is very rare) be trained to act as a shield to block incoming spells from hitting it's master. This is is very dangerous, however, because the intelligence of an ooze is different to that of other creatures. It's intelligence is random, chaotic and emotionless, meaning that is will often go rogue, attacking anyone in it's path to fulfil it's ooze purpose - to gain as much mass as possible.

Warfare

When there is no hope left to win a crucial battle, a less honourable commander might sacrifice their own forces to destroy the enemy and the battlefield, by bringing out a captive magic starved elder ooze. When on the battlefield, it will be bombarded by spells, and will explode into a colossal swarm of arcane jellies, which will flood the battlefield, laying waste to everything in it's path for miles. The huge danger of this tactic means that it is hardly used, any then mostly by evil humanoids.

Magic

The store inside an arcane jelly means that is is coveted by magi and adventurers in search of power. Through ingenious arcane contraptions, it is possible to leech the energy inside an arcane jelly, for use in magical item crafting and powerful rituals.