Yolawis is arguably one of the most dangerous Ultra Beasts discovered. A tangled, glimmering conglomeration of eyes, tentacles, and lights, Yolawis is a ravenous apex predator that strikes fear into the all the denizens of Ultra Deep Sea. At its center is a large, multi-irised eye that can tear apart to become a gelatinous mouth riddled with inward-pointing fangs. This mouth is only revealed when the creature is threatened or needs to consume a large object quickly. Yolawis prefers to use the secondary mouths in its tentacles to feed at a more leisurely pace, as its core is much more useful as an eye than as an input orifice.
Yolawis individuals are surrounded by a psychic field at all times, serving both offensive and defensive purposes. The field warps the minds of anything that enters it and even degrades the integrity of spacetime itself when amplified. Confusion is its preferred status ailment to inflict, and prolonged exposure can cause long-term hallucinations and paranoia. The psyfield prevents opponents from drawing too close and allows it to disable its prey when it closes in.
Sapient beings are not safe from its effects, either. Prolonged exposure to Yolawis' psychic energies drives humans mad, causing hallucinations, nightmares, and intense paranoia. For this reason, the research of captive Yolawis has been halted for the sake of the researchers' mental health. Those that have experienced the visions it causes and remained lucid report that they see what it sees, and it sees everything. In every direction, from every direction, every past moment, possible future, and alternate outcome within their psychic fields. What's more, victims are exposed to Yolawis' own thoughts, and some say that it expresses a malice unlike anything a human could imagine, and that it forms plans too horrible for the human mind to withstand even considering. It is from these short studies that Yolawis' secondary typing was determined to be Dark, and that their psychic field functions quite similarly to a passive, constant Dark Pulse, which has confirmed to be part of its moveset. Further observation in the field shows it gleefully toying with its food before killing and eating it.
Yolawis are as brutal in their parenting as they are in the hunt. Of a single clutch of hundreds of eggs, few survive to adulthood. The weakest are eaten by their siblings, and those that aren't the most cunning are devoured by their progenitor. The only ones that get to live are those that can crunch through the solid glass of a disused Nihilid skeletons, solve devious puzzles and mazes designed by their elders, and survive a day drifting alone at the surface.
However, some Yolawis fail these trials and still manage to survive. These individuals were lucky enough to develop all their claws and mandibles earlier than their peers, giving them enough strength to fight off the trial masters, perhaps snip off a tentacle or two in the scuffle. Fearing for their lives, they flee, and these outcast Yolawis have established their own small society separate from the cannibalistic mayhem of the main population. They are scholars and philosophers, and on the rare occasion the Divers stumble across their hidden sanctums, they will offer shelter from more dangerous creatures. Their psyfields are still unsettling for human researchers, but they do not seem to convey the same degree of hostility. Though their minds still cannot be fully grasped, the spiraling glyphs carved into the walls of their burrows may hold the key to Yolawis psychology.