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“Remind me again why we need a cow?” Martha asked, leaning against the TARDIS with her arms folded.
They’d visited a cattle auction, and the Doctor had bid a huge sum of money on the first cow down the chute. And here they were, out behind the auction house, the Doctor holding a cow on a rope and trying to drag the stubborn animal towards the open TARDIS doors. The auctioneers didn’t typically hand cattle over to customers with only a rope to lead them back to their vehicle, but the Doctor had managed to smooth-talk them into this stupid situation.
“Well, Martha,” he said with a grunt and another tug, “TARDIS maintenance, is why. I need this cow- come on! Please move?- because the TARDIS needs this cow.”
Martha blinked a few times.
“O…kay…so, why does the TARDIS need a cow? Because this- she’s a futuristic timeship, Doctor, I don’t see why you’d need a cow…”
“Well! Interesting thing about TARDISes- they were first made by marrying an ancient species of deepwater coral that lived in the depths of my planet’s oceans with sophisticated technology to create time machines. She’s still partly- or mostly- made of that deepwater coral-“
“Coral?” Martha echoed, “That doesn’t make sense. If she’s made of coral, wouldn’t you need to just…leave her in the sun?”
The Doctor shook his head, giving the rope another yank and convincing the cow to take another few steps forwards.
“No, no- Look, you want to give me a hand here? I’ll explain over lunch.”
“What?” Martha echoed, standing up and walking towards the cow, “Lunch, alright, but- what do you need me to do…?”
“Grab its ear or something and tug it towards the door, I don’t know!” the Doctor grumbled, “Bloody stubborn cows….anyway, We’re going to put this cow inside the TARDIS, lock the door, and let her get on with the maintenance cycle. And while she does that, we’re going to get lunch.”
Martha sighed and grabbed the cow’s ear, tugging gently and jumping back when the cow grunted and jerked its head away.
“Great,” Martha muttered, looking around for someone who might be able to help them.
From around a corner of the building, River Song watched the Doctor and Martha load a cow into the TARDIS. She shook her head in bafflement- what a strange man he could be. Devote your life to studying the ins and outs of a Time Lord’s history and you’d still run up against mysteries that nobody could ever hope to solve.
River waited patiently for the Doctor to lock the door up and walk away, giving it a good five minutes before creeping across the parking lot towards the towering blue box. Hopefully the cow wouldn’t be too much of an issue, she just needed to nip off and do a few things before she put it back. Tracking him down to this point had been a bit of a pain- somehow or other the auction records had made it onto the future Galaxynet, which had been a stroke of luck, but-
Oh, nevermind.
River stuck her key in the lock and opened the TARDIS door, breezing inside with a smile.
“Hello, sweetie!” she called without looking at the console, “Just need to pop off to Tanarys for a day or two, I’ll put you straight back.” She turned around and shut the door behind her- and froze.
Above the usual TARDIS hum, above the whirr of distant machinery and the faint whoosh of the Vortex wrapping around the dimensional reactor, above all the noises of machinery and mechanisms, there was a sound that River had never heard aboard the TARDIS before.
The sound of flesh ripping and tearing. A snap like breaking bone. The air was permeated with the scent of blood, with a whiff of slightly spoiled meat and unwashed animal hide.
She slowly turned around, staring at the bank of roundels to the right of the door.
Her eyes went wide and her jaw dropped in horror.
Emerging from dozens of the roundels were…creatures. Fat cylindrical bodies with translucent yellow skin, blobs of reddish blood and flesh visible inside of them. Their tops were crowned with short stubby tentacles, like petals around a flower- all of them latched on to the rapidly-disintegrating body of the cow.
They looked like tiny sea anemones, and they were eating the cow. They writhed over the carcass, wrapping around legs and ribs and pulling and thrashing-
All the polyps paused their writhing motions, and every light on the TARDIS dimmed. The hum sharpened to something fierce and angry, and River swallowed.
“Oh. Ah. Right, so, I’ve just remembered that I- had somewhere else to be! Yes. Sorry to bother you, I’ll just be off!” River spluttered, backing out the TARDIS doors and slamming them behind herself. She locked it up, picked a direction, and RAN.
“So…if she’s made of coral, how come the cow?” Martha asked as they strolled back to the TARDIS, “You said she wasn’t solar-powered, so…?”
“Well, on Earth, you’ve got several different types of corals. There’s types of coral that live in deep, cold water that don’t have zooxanthellae- er, algal partners- because they live well below depths where they can photosynthesize. Anyway, these deepwater corals are suspension feeders- they sustain themselves by capturing edible scraps instead of a symbiotic partnership with algae.”
“Like a sea anemone?”
“Exactly! Spot on, in fact. Well, on Gallifrey, the species of coral we bred into TARDISes are a bit like your deepwater corals- they lived at depths like yours and get from the water column- but ours were a bit different. Our cold water corals were carnivorous, with huge polyps for catching and consuming prey. You’ve got a few species like that on Earth, too.”
“So…the roundels…?”
“Are where she houses her polyps, yes. They’re dormant underneath the coverings. And sometimes she needs to perform maintenance on the organic parts of herself. So I’ll supply a non-sapient life form, which she’ll telepathically render unconscious and then disassemble on a molecular level. She’ll then use those proteins and compounds and reassemble them in her living components to grow and repair them. Simple!”
“Grow and- she eats them. She ate that cow?!” Martha spluttered, “Would she eat-?”
“A human? No, no. She only needs a little bit of meat once every decade or so, and if there’s no choice she can go without. She’d never eat a human…mostly because there’s not enough meat on one of you to bother, and also because you’re sentient and- what?”
“…Great.” Martha groaned, “that’s a huge comfort. The ship’s made of carnivorous coral and I might be on the menu.”
“I just said you weren’t! Gah, explain the basics of your ship’s biology and everyone loses their bloody mind…” the Doctor said with a groan, “No, Martha, the TARDIS won’t eat you, or me, or anyone else that’s sapient. That would just be daft, making a maneating time machine. The TARDIS is telepathic- she knows what is and isn’t an intelligent being, and she isn’t about to go snuffing out the life of something like you or me. But she’s still got to eat, and it’s got to be meat. Think of it like you. We went for lunch so we could stay alive- that cow was lunch for my ship so she can stay alive. You see? ”
“Alright…” Martha said dubiously, letting the Doctor unlock the door and stepping inside after him.
“That still doesn’t explain why we had to leave,” Martha asked, looking around for the remnants of a Sarlacc pit or whatever the TARDIS ate with. There was nothing- the console room was entirely as they’d left it.
The cow was conspicuous by its absence.
The Doctor spun around and gestured grandly at the coral struts and the ceiling.
“Well, Martha,” he said, “It’s very rude to barge in on a lady when she’s got her polyps out. Simple table manners, really. My TARDIS is the finest ship in the universe, and as such, she’s got good manners and won’t eat if there’s anyone about.” he started setting switches, considering as he twiddled a knob to set their next location.
“What do you think she’d do if someone DID barge in midway though…lunch?” Martha asked nervously.
The Doctor stood up straight, brow scrunching as he considered that.
“I don’t know!” he said with a broad grin, “But I’d hate to be the silly bastard who finds out.”