*All alien language is translated as best as possible. Certain words will be selected closely matching to their meaning. *
The maggot in front of them came from another swamp not too far. It had found a dickroach which is an ancient ancestor of cockroaches that are still alive in the present day on planet Xen.
It is unknown how they ended up on Earth millions of years ago but it was probably through one of the many interstellar modes of disease/pest transmission.
The most likely cause was that some of the dickroaches were left behind from a spaceship that had landed on Earth at the end of the Cretaceous period 65 million years ago. The dinosaurs went extinct after they were eaten by the dickroaches.
Aliens paleontologists that have been studying Earth, for example, a Gray might ask why would the dickroaches cause the extinction of the ecosystem. After all, they were only as big as the pachycephalosaurus. There were plenty of carnivore predators bigger than that like the T-rex, giganotosaurus, Spinosaurus etc. The dickroaches were about twice as tall as humans and 10 times larger in their other dimensions.
Being giant insects, the dickroaches were relatively fast breeders compared to the reptiles. They ate everything that they can hunt and when they ran out of food, they eventually hunted in large swarms, eating other packs of dinosaurs and larger meat-eating dinosaurs.
Herbivore dinosaurs were easy. When swarms of dickroaches surrounded one, they kept their distance as they were afraid. A few of them would close in to bite and slash but they drew back when the Brachiosaurus tried to stomp and swipe at them with its head.
It squashed some dickroaches but a few dead didn't matter to the swarm. The savages would drag their comrade's body back and cannibalised it.
Once one bit it on its back leg and stuck to it. The Brachiosaurus brought its head with its long neck to the back to look at the roach. It cried out in pain and tried to pull the roach off but the roach stabbed it in the face with its barbed legs like a man who was swatting a fly away to eat in peace.
The Brachiosaurus was essentially a reptilian giraffe that's never fought or killed in its life. It had no chance.
Seeing that the Brachiosaurus was practically harmless and useless, the rest of the dickroaches charged in like starving beasts. They tore into its flesh from top to bottom, causing the dinosaur to fall in a sea of roaches.
It was bare bones a minute later. All the internal organs were scrapped.
The roaches carried on to the top of the food chain. They got more confident. The big predators got sick of eating roaches.
At first, the roaches didn't dare fight the giants, a few stomped or hundreds of roaches would get netted like fishes in the mouths of the gigantic predators but the rest ignored it.
Finally, they started hunting the largest of the carnivores, the Spinosaurus.
The antennas of the roaches have picked up the scent of the last of the Spinosaurus. The roach's versatile survivability and adaptation is owed to its enormous array of useful genes. They could eat anything that moves and detect what major nutrients that they were getting from a meal. They could even eat paper if they were stuck in the printer room.
Indeed, they would even survive the toxic environment after a nuclear blast. The roaches would mutate and survive better than anything else when exposed to radiation. Humans cannot hold a candle to a roach.
Dickroach antennas were probing the air when they picked up the scent. The front line moved and all the other roaches followed. The Spinosaurus heard the sounds of roach legs stampeding the forest floor. It had run away from its mother who drowned five minutes ago in a sea of roaches.
Being the last of its kind, it gave a lonely but proud roar.
Soon, the first line of roaches came out of the shadows of the tree line into a clearing. A fitting arena for the last battle.
The frontline stopped before the dinosaur and their antennas began whacking the air like crazy. They were excited. They had found prey.
The front line was reluctant but the crowd behind them pushed them on. The first wave was wiped out by a swing of the head. Then a huge group of roaches were munched on. Later, some of them were stomped.
However, more and more roaches filled in the vacant spots ahead.
When some of them latched onto the legs, the Spinosaurus brushed and bit them off but it was difficult since they were smaller and hard to grab. Because the Spinosaurus missed a couple of spots, the speed at which the roaches were rid of was much slower than the rate at which they hopped on.
This charge accelerated as the roaches behind became more confident seeing the Spinosaurus cry out in terror.
The roaches hanging on the face and back ploughed through and dug in. Some stayed outside and pulled its eyeballs out.
When the roaches swarmed the Spinosaurus, there wasn't much space for the others who climbed on top. Some at the forefront went inside the Spinosaurus' guts to feast. When the outside roaches met with the inside roaches, there was no more flesh left and they scattered to look for more food.
The smaller animals were not sustainable for the bigger dickroaches and so it was more filling when they cannibalised each other. As years passed by, the roaches have evolved to become smaller to better match their resources.
That was how it was for Earth. On Xen, the dickroaches were in the middle of an evolution. They were the size of small dogs.
A roach had come to a swamp to drink some water. Although the water was dirty, the roach had high resistance to dirty water as well as other toxins. Roach genome covers everything.
That was when the abnormally long slither found its prey.