Weighing 11,000 pounds and standing just over 12 feet tall, the atrocious crossjaw is Serinaustra's largest land carnivore, and the biggest terrestrial scrounger ever to live. An apex predator, this huge, fierce descendant of the belligerent brawler has evolved to hunt the larger giraffowl and most strongly-armored lumps, acquiring an unusual and specialized tentacle arrangement to do so. In this genus, the four facial appendages have become the primary jaws, and are powered by gigantic muscles running up the skull and down the neck.  To maximize their bite force, the tentacles have developed an asymmetrical shape, with the right one angling down to mirror the top jaw, and the left one curving oppositely upwards to match the lower. Each of these reversed side tentacles now functions in tandem with its cosponsoring vertical one, and has become partially connected with a cheek-like flap of skin, which helps hold them together as well as keep food in the mouth while chewing. The end of each tentacle carries a massive meat-hook of a talon, up to 18 inches long, while the inner surface of each is lined with a dozen additional keratin teeth, serrated like steak knives. Like earlier, distantly related grapplers the tentacles of the crossjaws are ossified with skeletal elements, rod-like bones in groups of three supporting powerful tendons that are operated by the muscles of the head and neck. This lends them great strength and stability, and produces a vastly more distinct and bizarre-looking skull than in the trunkos, which have entirely soft-tissue trunks that do not have any bones at all.

The atrocious crossjaw is an unrivaled hypercarnivore which preys on the biggest and fiercest of prey species across Serinaustra's northern regions. It is widespread in wooded regions and open wetlands, only avoiding the center of the continent where the thickest forests and miring swamps limit their spread. Solitary and territorial, their only real enemy is their own kind, and adaptations which aid them in tackling dangerous prey - huge jaws, horns, and spiked cheek flanges which serve as shields to protect their face from blows - are also used in intraspecific combat. Their vicious tentacular jaws allow them to grab the similarly defensive facial flanges of the biggest and meanest grumplumps and similar species, and pry them away from their necks to deliver a deadly throat bite, while they are surprisingly fast and agile, avoiding defensive attacks with quick dodging maneuvers. The tail of crossjaws is very long but stiff, formed from a few greatly elongated but fused bones, and as in most scroungers can flex at the base to provide additional balance and stability.

Too big to brood its eggs, and having no pouch to put them in like the trunkos can utilize, this genus of scrounger has had to adapt an alternate method of incubation which relies on using the heat produced by decomposing plant matter to brood their clutches. Females pile up leaf litter and plant debris into immense mounds up to 10 feet high and 30 feet across, which become compost heaps, producing heat at their centers in excess of 140 degrees Fahrenheit as this material begins to break down. The female lays a typical clutch of six to ten eggs near the top of the mound at a very staggered interval of every 5-10 days, and then tends the mound for as long as three months to maintain a suitable incubation temperate of around 100 degrees while they all develop. She opens the mound if it gets too hot, and adding more insulating material over the eggs if they get too cold. This method of incubation originated in an earlier, smaller species which began constructing larger and larger nests to support their own body weight while sitting over their eggs, which could be kept in a depression at the center of the nest and so not bear the direct weight of the siting mother. As crossjaws became too heavy even to do this safely, they began to rely on the heat which was inadvertently produced by amassing so much plant matter into a condensed pile to do all of the incubation, requiring the mother only remain near to tend it and ensure temperatures remain stable. Unlike most scroungers, parental care stops at hatching, and the chicks are born fully able to fend for themselves. Because the eggs do not have to bear the weight of a sitting parent during incubation, and are instead cradled evenly on all sides by soft soil and leaf litter, the shells are thinner than in other birds' eggs, which paradoxically has allowed them to be bigger, as long as 20 inches, and weighing up to 38 lbs, without becoming so robust as to prevent the chick inside from being able to hatch. The newborn crossjaw, weighing as much as 30 pounds, kicks its way out of its shell, rather than using its beak or jaws, and is born with an especially sharp, long middle talon, which then becomes dulled with increasing age. Predation of these small young is significant, but offset by the large number of young born at a time, and their staggered maturation which means no more than one is likely to leave the nest at a time, so that predators cannot possibly be present to catch all of them. Adult size and sexual maturity is achieved around 9 years of age, with a maximum lifespan of 45 years. 

There is one animal on Serinaustra that not even an atrocious crossjaw can kill once it has reached adulthood. The earth itself shakes as if with fear with each of its slow strides. Ancient trees tremble in its wake. Birds take flight as the largest animal on Serinaustra, and one of the tallest in all the world, parts the forest with its grandiose crown. Its immense crest is semi-transparent, refracting the early morning sunlight through prisms in its structure, producing a flickering, multicolored display like stained glass. There is nothing else like its beauty in any other animal. He is incredibly powerful, and equally beautiful - and he knows it. He opens his beak and bellows a roar so loud, so vast, that it carries for twenty miles around as vibrations through the ground; roughly the area of his territory, in which no rival will dare set foot.

He is a starscraper, an adult male of a species descended from the skybreaker. A champion, for very few live so long and accomplish so much as he has. He holds an entire forest in the clearview mountains - now scarcely more than lightly rolling hills crowned with tall trees - as his territory, fending off challengers, none who approach his size. The largest giraffowl ever to live, he is 60 years old, and still immature. His growth is indeterminate; while it was fastest in his youth, he never ceases to grow taller, still by several inches each year. Every female in this woodland is a willing mate to him, some thirty or more. There are no rival males within a head's height of him - for now - and so he has almost nothing to worry about. Not a single predator could threaten him now, not on this continent at least. If there were ever a winner in the book of life, a single individual success story, it would be him. 

Starscrapers can grow to just over 50 feet high, though most females are barely half so tall. Only the males, with their incredibly varicolored crests, really benefit from endless growth, for to breed means to shove out the competition, and the way to do that is to be bigger. Females begin reproducing at six years of age, when they may be just 18 feet high. Males, if they ever mate at all, will take more than five decades to be competitive. Mortality in both sexes is high early in life - like most giraffowl, childhood means a harrowing years-long age as a small, vulnerable flying bird, and only a small percentage of those reach their flightless adolescent stage and fewer yet sexual maturity. But once taller than any land predator, mortality lowers for several decades. In females, it begins to increase after the age of 35 years; continuous reproduction reduces their vigor. Males, in contrast, have hardly any risk of death at all until they approach fifty years, an age most females don't live to see. Now big enough to challenge each other for territory, male starscrapers kill one another off in tremendous battles with their vast crests. At such height, a single fall is fatal. A male determined to mate must excel in patience, biding his time for many years before he makes his approach against his rival. He must be able to overpower him immediately, to toss him aside before he is thrown instead. Many males, impatient, calculate badly. A single fight may be all they get, and most will lose.

But the male who now rules this forest waited longer than any, growing enormous. When at last he emerged from the treeline and challenged the former ruler, he towered overhead, his eyes meeting the peak of the other's crown. Bewildered, the old king fled, and so he lived. The new king, by strength of sheer size, rules now without bloodshed, for none will challenge him. But even his reign will be temporary. He has an edge against all other males currently alive - not one will catch up to his size. But now, in his old age, the very thing which brought him success will soon become his enemy.

Starscrapers, if not killed by illness, predation in their youth, conflict, or accident, will all one day be killed by the inability of their bodies to eventually support their ever-increasing mass. They are built for height at the expense of speed, strength, or stability. Their necks are longer than their legs, and their legs, thin and gracile, are already near the very limit of what can support them. Their anatomy is perfectly designed to move in thick forest, between the trunks of trees, and to reach branches high off the ground as quickly in life as possible, without the need to balance their height with a huge amount of weight as cygnosaurs do. But this means that, inevitably, any which live long enough will outgrow the capacity of their legs to carry them. The oldest starscrapers eventually topple like the trees around them, as the bones of their legs crack beneath their weight. Natural selection doesn't stop it, for until then, growing ever taller is a tremendous advantage. By the time that their bodies fail, males will likely have already reproduced; they may have sired thousands of young, and it will be necessary for new males to take their place and maintain genetic diversity.

So though now the new king stands tall, rival males will be patient. Never to catch up to him, they don't need to. The bigger they are, eventually, the harder they will all fall. Like a whale-fall at sea, the body of a fallen starscraper then feeds thousands of smaller lives. Among the scavengers comes the atrocious crossjaw. Biding its time through the starscraper's life, it still gets its fill in the end. He might not have killed it, but he didn't have to. To this apex predator, that is a pro, not a con. He will relish the spoils all the same.