Fear What You Know
"An expedition team encounters a familiar 'plant' while on Erebus VII."

2043 Hours, 21 January 2557
Expedition Course: UNDERBRUSH PENETRATOR, Unknown Location
Erebus VII – Remote Garden World, Human Space

Spartan von Essen trailed after his expeditionary group for the fourth time in two hundred meters. It wasn't like he tired or had reason to fall behind, something just kept putting him off.

Erebus VII was an interesting world, to say nothing more on its utterly alien nature. Humanity sailed the stars for a little over two centuries, and terraformed, colonized hundreds of worlds. It was so easy to take things for granted. Even after making proper first contact with the many Covenant races and fought a war with them, they ended up being deceptively human in their own rights.

So, it was flabbergasting to step foot in an untouched biosphere, unique supposedly and only to itself. A true standout. So why did he keep seeing something horrifyingly familiar at every turn?

Did his eyes fail him, or did he face a true ungodly force down here?

This was the sixth time he'd seen it. That brown slick surface rippling like a surgery-freed lung or heart, pulsating in rhythm. Bulbous and rubbery like a wet, thick balloon. And it and the others were large, easily the size of an entire rose bush. And dozens more of the swells grew atop the big one, and around it in the muddy alien soil. They all squirmed as if more alive than in principle. Cancerous in appearance.

He didn't want to say it, for fear of realizing his rationale – his rationalized fear.

Von Essen knew what the others would say. They would call him crazy. Right? But this was a completely alien world, one only recently set foot upon by humans in the space of mere weeks to a few months.

Licking his lips behind the fog-trapped visor of his MJOLNIR helmet, he barked into the radio. "Team hold. I got something of concern."

The blue waypoint markers of his team paused in movement, some taking a knee. The furthest marker was already making its way back down the satellite-designated trail as its speaker responded in a huff. "What is the hold up now? We're explorers, what could possibly be worth a break?"

Von Essen didn't bother responding, keeping his BR85 battle rifle slick against his chest plate and his lone plasma weapon, a Covenant plasma pistol magnetized to his thigh. He recalled his post-War adversary identification training; plasma could temper most biological threats.

After many moments of waiting in tempered silence, the radioed voice arrived in the open – coming to stand next to the Spartan. The woman, dressed in a procured and wrongly-fit Marine Corps jacket and environmental mask, stood barely up to von Essen's chest.

"So, Spartan. What's the holdup?"

Von Essen shrugged his shoulders and gestured to the swell colony separated four feet from himself. "It's this thing—"

"It looks familiar Spartan but it's not what you think it is."

The Spartan paused, expecting an explanation but none came. He asked, "Then what is it?"

The science expedition leader grumbled and waved her hands around in mild frustration.

"Do I really have to babysit three Marines and a paranoid Spartan… It's like you not only can't think for yourselves; you soldiers can't even take care of your own jobs."

Von Essen made to interrupt, defending himself and the escort. "Doctor Stein, your comments are highly unprofessional and I don't—"

"What are my requirements of you and the Leathernecks on this trip?"

"Ma'am—"

The doctor interrupted once more, "Humor me, now."

Von Essen sighed, "Scan visible flora and fauna along the designated path. Avoid overexposure, collect samples where possible."

Doctor Stein glanced up at the Spartan. "Well, I guess you're at least good for that much. The Marines couldn't even remember that."

"To be fair, ma'am, we weren't given a crash course on what to investigate, and Command ruled that we keep a small team, so we couldn't fit your assistants this time around. The Marines are just trying their best."

The doctor sniffed at the rebuttal.

"Still, what is it if it's not—"

"Mummyvine."

The Spartan did a double-take, "What? I've—can you repeat that?"

"Mummyvine. Arcadian climbers or creeper plant. They're a type of spore-vine flora that used to be native to Arcadia before it was glassed by the Covenant."

"I'm not familiar with the species."

Doctor Stein thrust her data pad at the unsettled Spartan. "Read it."

Von Essen gingerly took the data pad in one hand and swiped above its plexiglass screen. The on-board data jumped over a wireless connection to his suit computer, cataloging the information for his own data set. The Spartan handed the tablet back to the doctor and began to read for himself, the doctor huffed at the nonverbal interaction but already made to turn around.

Even so, the said unhelpful Marines were beginning to arrive as well to assess the commotion between Spartan and doctor. No one spoke to them, thoroughly occupied. Still, von Essen couldn't help but feel sympathy for his subordinates.

They already verbalized their distaste for this assignment in private. They didn't want to be here. Doctor Stein didn't want to be here. Von Essen didn't want to be here. The said doctor's insults were certainly heard, unappreciated, but thoroughly ignored.

The data entry catalog was thin but straightforward, short enough that von Essen could get a fair picture without holding up the expedition into the Erebus VII evening. How considerate of the good Doctor.

Mummyvine, a species of highly invasive Arcadian climber plants and once native to Arcadia was discovered in 2461 around the time of planetary colonization efforts. Hardy and spread through air-propelled spores, they sought out all potential spaces for water sources and then proceeded to absorb them like a vacuum. Other plants, animals, even humans were susceptible to it and lead to a health emergency in the same decade of first discovery where Arcadian farming families, livestock, and crops failed on a grand scale near the planetary equator.

Turned out exposure to Mummyvine got into their bodies and food supply and once infected, sucked their bodies dry of water – leading to mummification on an epidemic scale. In the following decades, the invasive species managed to jump biospheres on Arcadian freighters but were quarantined quickly after several notorious outbreaks on neighboring colonies. Since the glassing of Arcadia, the plant was on the endangered species list but not that anyone really cared beyond some prickly scientists.

Great. So, von Essen had the luck of being the first human to rediscover a very dangerous and nearing-extinct plant species. That wasn't going on his post-service resume.

Still, something about the encounter felt off to the Spartan. A little note at the bottom, attuned to his clearance level remarked: "shares visible identification qualities with Inferi redivivus."

"Doctor Stein, how are you certain this is Mummyvine? The vinery, spores, and these… blisters? They have a brown-and-orange coloration to them. Mummyvine is described as a green-and-grey coloration."

"It's Erebus, Spartan! Everything is fucking brown-and-orange on this fucking humid rock. Let's go already."

So much for that… Von Essen's glance to the Marine escorts received casual shrugs.

One Marine, Corporal Tomas, made a passing remark as he turned away. "I mean… I do see it? It does look like the Flood from simulations. Not that I would know well, I wasn't at Voi."

Deciding maybe the doctor was right and he was just being paranoid, he took four steps – following along the designated trail once more. Falling into step with the shorter strides of the Marines and keeping a careful eye on Doctor Stein's marker as it strolled ever ahead of and away from the security entourage. He didn't look back to his concern.

Well, that was before he heard a rustle. Then a bubbling, squelching 'pop'.

Turning around alone out of curiosity, von Essen detected a brief, low roar like a sickly horse.

His dew-covered visor made it difficult to make out clear detail but he swore he saw something. It was kind of small, cat-sized. The shadow scuttled across the trampled ground and into the underbrush. A few thoughts crossed the Spartan's mind as it disappeared.

Squid-looking. Little tendrils. Did he see that right?

A/N: A late Halloween entry intended for Halo Fanon's The Weekly contest. Takes a few elements from different parts of the wider Halo expanded universe to throw together this less-horror, more-curiosity type of short story. I'll let you in on a little secret, visually the "Mummyvine" is supposed to be the ambient plant life that appears in The Lost zombie missions in XCOM2: War of the Chosen. Alien vines are kind of a cool concept so they became the throwaway inspiration for this entry. Thanks for reading, pass me some feedback – I enjoy criticism.