Ice

The comet rapidly grew larger at a rate visible to the naked eye, then streaked past at high speed nearly ten kilometers from the cell cluster.

By the time Huo Gu reacted, the comet, dozens of kilometers in diameter, was only three hundred kilometers from the planet.

At the comet's current speed, barring any accidents, it would collide with the planet's surface at a tangential angle within minutes, drawn in by the planet's gravity.

Everything that had happened so far was normal. The comet's appearance was somewhat unexpected, but only because Huo Gu had been focused entirely on searching for the unknown enemy and had instinctively overlooked it.

Then, the next second, the world began to behave abnormally.

A powerful gravitational source appeared out of nowhere, so abruptly and without any warning.

At the same time, the cell cluster slipped out of its orbit, having lost the planet's gravitational restraint.

The gravitational point could not be seen, but it could be felt. From the deformation of the cells inside the titanium alloy shell under stress, along with comparative data on the planet, Huo Gu could roughly infer some information about the gravitational source—it had the same gravitational strength as the planet, but occupied a different position in space.

From an observer's perspective, it was as though the planet's center of gravity had suddenly leapt out from inside the planet.

This shift in the gravitational point lasted only a few seconds, but that was enough. The comet, which should have struck at a tangential angle, barely skimmed past the boundary between the troposphere and stratosphere, roughly twenty kilometers above the planet's surface.

During that pass, the comet broke apart. With an average density of only 100 kg/m^3, it had already crossed the rigid Roche limit between itself and the planet, shattering into five comet fragments between five and ten kilometers in diameter.

However, since its velocity was far greater than the escape velocity of the planet where Huo Gu currently was, even after breaking apart, the fragments did not fall to the surface. Instead, they brushed past the planet and went their separate ways.

Only after a long while did Huo Gu snap out of its daze, unsure what words could describe what it was seeing.

Its gaze shifted back and forth between the planet and the place where the gravitational source had appeared, and a terrifying thought arose.

Could that thing be...

Not good! The altitude is dropping!

Because of the gravitational disturbance just now, the cell cluster had broken away from its original orbit and was falling toward the planet.

For the moment, Huo Gu set aside the matter of the gravitational source. It needed to deal with the immediate problem first.

At its command, the cone-shaped cell cluster turned around, its sharp nose pointing toward space and its tail toward the planet's surface. Balance wings extended from both sides of its shell.

Since the enemy was not in space, Huo Gu had no need to focus on space for the time being. Before that, however, it needed to recover the cell cluster that had been launched into outer space.

Huo Gu had no intention of abandoning this cell cluster. That did not align with its principles of action, even if it was merely a biological tool.

Its descent accelerated. Air scraped against the titanium alloy shell, and a long plume of flame enveloped the cell cluster, just as it had when it was launched into space. Only this time, it was returning to the surface.

When the cell cluster was still more than thirty kilometers from the ground, the tail thrusters ignited, greatly slowing its descent.

Then, an airbag unfolded from the top of the cone. Its other end was connected to liquid hydrogen used as fuel. In the normal atmosphere, the liquid hydrogen rapidly turned into hydrogen gas and filled the airbag to its limit.

Its descent slowed even further. At this speed, the strength of the titanium alloy shell meant the cell cluster was no longer in any danger, allowing Huo Gu to turn its attention to other matters.

Hostile tornadoes, lava, and lightning still ravaged the planet, destroying the root-stem system.

The unknown entity had been attacking the root-stem system for quite a long time, even without Huo Gu intervening to obstruct it.

That was because the original plan had been in preparation for a long time and covered an enormous area. Organic materials had been stockpiled by the hundreds of millions, and various forms of attack had been anticipated in advance, with corresponding defenses prepared.

Huo Gu did not react immediately. It merely observed. After combining all the information from before, it had already formed a rough idea of the enemy's true identity.

But the idea was far too absurd. Even Huo Gu, the one who had proposed it, found it difficult to believe.

Moreover, there were still aspects of this speculation that were difficult to explain, such as the enemy's hostility toward the root-stem system and massive biological tools like Octahedron.

Just as Huo Gu was considering how to formulate a new testing plan to verify its conjecture, an abnormal condition on the planet caught its attention.

First, the rain stopped. The dense cumulonimbus clouds dispersed overnight. From then on, a day on this planet was no longer murky and featureless, but divided into day and night.

During the day, the slowly rising ruler of this planetary system—the star—could be seen.

At night, with no light pollution whatsoever, the stars filling the sky made the darkness less lifeless.

This signified that the planet's Early Rainy Sea Era had ended.

At the same time, prompted by the comet's earlier pass over the planet's surface, global temperatures began to plummet.

The source of it all lay in the struggle between Huo Gu and the unnamed enemy, as well as the five comet fragments that had escaped after being torn apart by tidal forces at the Roche limit.

To sustain its enormous form, Octahedron constantly relied on muscle cells to consume massive quantities of methane from the atmosphere. This caused the atmospheric methane that kept the planet warm to drop sharply, which was the fundamental cause of the planet's cooling.

Although carbon dioxide was also a greenhouse gas, its properties allowed it to dissolve in water or be converted into oxygen by oxygen-producing microorganisms. Therefore, carbon dioxide could not fully serve as insulation.

Though the comet had merely passed by, its low temperature still acted like a fuse. Under the fuse's effect, the cause transitioned toward the result. Like falling dominoes, once the balance shifted even slightly, the change rapidly intensified until it became uncontrollable.

Of course, none of that was the important part. What mattered was that the changes occurring on the planet were extraordinarily fast, as though someone had pressed fast-forward on a videotape. Day and night flickered on and off at high frequency like a brat playing with a light switch.

It took Huo Gu quite some time to understand what was happening—its perception of time was slowing down.

The temperature dropped even further. In Huo Gu's field of vision, ice spread across the sea like weeds, quickly claiming dominion over both ocean and land. Icebergs rose from the ice one after another, as though this were a virtual game world.

The last sight Huo Gu saw was a frigid world draped in silver, blanketed in ice and snow.

After that came darkness from behind, as though it were falling into some bottomless black hole.