Nullworms are the only known organisms believed to emerge from the Nothingness. They are dangerously destructive on a universal scale.
They emerge out of nowhere, cause massive annihilation, then are believed to return to the Nothingness. Experts remain divided on the precise mechanism. Some argue that Nullworms must exist within the Nothingness in some incomprehensible state, allowing them to switch between being and non-being. Others contend that they are a byproduct of the Nothingness itself - something that gestates in the absence and is violently expelled into existence, only to be annihilated again as a natural consequence of their short, destructive lifespan.
No living specimens have ever been studied. Even the corpses of slain Nullworms eventually stop existing after a variable period of time (ranging from hours to weeks), leaving behind only battlefield recordings and survivor testimony for analysis.
Nullworms are planetary-scale horrors. Mature specimens reach thousands of miles in diameter, with bodies of such immense length that their full extent is difficult to gauge even during active feeding frenzies. They possess a long, segmented, worm-like form of dark, glossy chitin that seems to absorb light itself. Relatively small glowing orange eyes line the sides of the head and continue to emit a faint, persistent light even in death. The entire front of the face is dominated by a colossal circular maw lined with concentric rows of teeth capable of shredding planetary crust and mantle.
Nullworms are indiscriminate and voracious. They swarm interstellar objects in huge numbers, consuming planets, stars, and other celestial bodies with terrifying efficiency. Their feeding frenzies can destabilize or completely annihilate entire solar systems in a matter of days. Accounts from survivors and the soldiers of the Interuniversal Defense Coalition describe them as relentless, single-minded engines of consumption that leave nothing but rubble and void in their wake.
If Nullworms are ever detected within your universe, immediate evacuation of the entire universe is strongly encouraged. The Interuniversal Defense Coalition and various multiversal relief organizations maintain emergency beacon networks and rapid-response ferries precisely for this purpose. Because they phase in and out of existence, once a Nullworm incursion begins, conventional containment is considered impossible; the only viable strategy is rapid, total exodus. Their sudden appearances are treated as one of the highest-tier existential emergencies in the Sphere.