There have been plenty of instances where badasses from Warhammer 40K have taken on giant beasts one-on-one.
The power of a Ultralisk can be compared to the smallest Titan class of the Titan Legions—the Warhound. Standing at 15 meters tall, the Warhound might be shorter than a Ultralisk, but as a proper Titan equipped with ion shields, large-caliber cannons, and giant chainswords, the outcome of a 1v1 between a Ultralisk and a Warhound is hard to predict.
As for the more advanced Titans, a Ultralisk might only reach up to their knees. It would take an even larger Bio-Titan to contend with them.
Back to the present, the Ork Warboss charges toward a Ultralisk atop a Squiggoth. Even though the Squiggoth is much smaller than the Ultralisk, the Ork Warboss shows no fear.
He is the BOSS, the biggest of the big!
How could he possibly be intimidated by a mere oversized bug?!
The Ultralisk, on the other hand, doesn't give the Ork Warboss a second thought. In its eyes, the Squiggoth poses a slight threat, but the three-meter-tall Ork Warboss is nothing.
When the Squiggoth crashes into the Ultralisk, the latter uses its massive scythe-like claws to lift the Squiggoth into the air—no wonder some call it the 'Great Bull.'
The Squiggoth simply isn't big enough, strong enough, or WAAAGH! enough to match the Ultralisk. The Ultralisk's sharp blades slice the Squiggoth in two, drenching the ground in blood.
But the Ork Warboss leaps onto the Ultralisk's head, raising his chainsaw axe high.
"WAAAGH—!"
With a furious roar, the Warboss brings his axe down, actually cracking through the thick chitinous armor plating on the Ultralisk's head.
That armor is the hardest part of a Hierodule or Ultralisk—multiple layered, multi-faceted chitin plates protecting the head, allowing them to smash through buildings. Yet, it was split apart as easily as paper.
The pain causes the Ultralisk to let out a roar of agony. It rears up on its hind legs, standing almost fully upright. The Ork Warboss struggles to keep his balance, nearly thrown off.
But he sinks his axe deeper into the Ultralisk's armor, stabilizing himself.
'Not the head, not the head, not the head.'
The Ultralisk's head is its most obvious weak point. That few-meter-wide head is just the right size for the Ork Warboss to potentially destroy in one hit. One solid chop from the Warboss could end the fight.
The Swarm Overmind sweats bullets for the Ultralisk.
At the same time, the Overmind laments.
'It's not that I don't want to help. Even though I possess psychic power far beyond that of an ordinary psyker, using psychic abilities to attack Orks is a foolish move.'
Orks possess the WAAAGH! field, which is itself a unique application of psychic energy. If the Swarm Overmind were to use its own psychic power against the Orks, it would essentially be pitting itself against the combined WAAAGH! of every Ork on the planet.
There are cases in the lore where Tyranid Zoanthropes have had their heads exploded by Ork Weirdboys when attempting psychic attacks. Until the Ork numbers are reduced, the Swarm Overmind cannot engage in a direct psychic clash.
Also, don't think about using Ork DNA to enhance the Swarm.
In the lore, Orks are a war weapon created by an ancient race in Warhammer 40K, the Old Ones. Their DNA is locked with genetic safeguards. Even the Tyranids cannot make use of their DNA, so it's unlikely the Zerg Swarm could either.
'Hang in there, Ultralisk, hang in there!'
Although injured, the Ultralisk isn't in mortal danger from the Warboss's attacks just yet.
The Ork Warboss also realizes the weak point isn't the top of the head. He glances down, toward the Ultralisk's head hidden beneath the chitin plates.
He immediately leaps down, landing on the Ultralisk's head. Gripping one of the spines on its head with one hand, he swings his axe with the other, aiming for the Ultralisk's face.
'NO——————!!!'
The Swarm Overmind panics. Damn it! The resources spent on this Ultralisk are secondary. Without this Ultralisk mowing down the enemy, this battle might be lost.
'STOP, RIGHT NOW!!!'
The Overmind, who just moments ago was determined not to intervene, now takes matters into its own hands.
Terrifying psychic power instantly spreads across the entire planet. This powerful being, created by one of the ancient Xel'Naga, reveals the immense psychic might that allows it to command the Zerg Swarm.
The sky above the battlefield churns with violent thunderstorms. The Ork Warboss is momentarily stunned by this spectacle, missing his chance to finish off the Ultralisk and getting thrown off.
'I, am the Swarm!'
That terrifying psychic power is so radiant, so conspicuous, that it stands out even in the vast, boundless galaxy.
A Tyranid Hive Fleet detects this psychic signal and begins adjusting its course, heading toward this planet.
Tyranids love to devour psychic beings.
'I, am the Overmind!'
Far away on Holy Terra, within the Golden Throne, a faint glint flashes in the eye sockets of the giant skeletal figure.
For ten thousand years, the Imperium of Man has been collecting psykers with powerful psychic abilities. In one of the Warhammer+ animated shorts, there's a scene of a Custodian personally collecting a psyker.
These psykers will serve as fuel for the Emperor.
Originally, it should have been Magnus who sat upon the Throne. But now, the Emperor seems to have found a more durable fuel source—an 'existence' he finds both familiar and alien.
A psychic power of this magnitude should burn for quite some time.
'I, am the Blade... wait, no, I, am the supreme Overmind of the Swarm!'
Meanwhile, within the Warp, the four Chaos Gods briefly turn their gaze toward this planet. The Gods aren't particularly interested in this species reminiscent of the Tyranids.
It is neither Khornate nor Slaaneshi, neither Tzeentchian nor Nurglish.
But the Dark Gods decide to send a couple of Greater Daemons to test this 'Swarm.' At the very least, an existence with such potent psychic power could make for an interesting 'plaything.'
Back on the planet, the Swarm Overmind faces the terror of the Orks head-on. Although it is connected to all Zerg units and possesses tremendous psychic power, the Ork WAAAGH! field operates on a similar principle and resists the Overmind's psychic onslaught.
Psychic storms surge through the Ork ranks. These deadly white lightning storms are lethal; no Ork can withstand them for more than three seconds.
However, some Orks, witnessing the psychic storms, have sudden epiphanies. Their eyes glow with white light as they awaken to psychic power right on the battlefield.
Ork psykers are crude and unstable. A few Ork Boyz who awaken emit psychic energy, their bodies crackling with lightning. The next second—*BANG*—their heads explode, dead beyond doubt.
This is normal. Nothing about Orks is particularly stable, and psychic power—already a somewhat temperamental force—becomes even more volatile in them.
The psychic explosions from their deaths cause significant casualties among both the Orks and the Zerg.
A few lucky Orks manage to control this power. Their eyes glow white as they simply raise a hand, unleashing bolts of lightning from their fingertips that sweep across the Swarm's lines, destroying countless Zerglings.
"Peculiar enemies."
The Cerebrate Zasz observes this and orders the Hydralisks to prioritize targeting these Weirdboyz.
But psychic shields materialize around these Weirdboyz. *Ting, ting, ting*—the shields deflect the Hydralisk spines.
This is precisely why the Swarm Overmind didn't want to use psychic power. Now that it has, it must see it through to the end.
'Come on then! Let's see if my power is greater, or if this planet's WAAAGH! is stronger!'
The planet's weather shifts according to the Overmind's will. Gales sweep the battlefield, the ground cracks and splits, and the entire warzone begins to change according to the Overmind's desires. The power it displays truly lives up to the title of Swarm Overmind.
But this is the Warhammer 40K universe.
Its current power probably doesn't yet match that of a demi-god of the Warp. It might be comparable to Magnus the Red during the 30K era.
Maybe...