It was a relatively quiet morning in the flat, the windows half open, relative silence pervading the corners of the open and rather cluttered room.
Crowley looked up from a potted plant. "Do I detect a hint of perturbation?"
Aziraphale stood in the doorway, damp, mussed, and wrapped in a towel, tortoiseshell glasses slightly fogged. "You do." His voice was slightly clipped. "I'm trying to take a bath."
Crowley blinked. "…thank you for telling me."
Crowley sat up, carefully. "I'm sorry I don't believe in the cleaning power of Clorox, but-"
"No, that's just fine, I've seen worse. But-"
"You've seen worse? Where have you been? That's just obscene-"
"A.J. Crowley, what is that thing in your bathtub?"
The demon winced. "Oh. Right. That."
"Yes," hissed Aziraphale. "That."
Crowley straightened, giving the potted plant a last stern look. "I'm not done talking to you," he warned, then turned to fully face the irate angel. "I hope you didn't drain the tub."
Aziraphale adjusted his towel. "So you knew about this and didn't mention it?"
"You forgot? How can you-" Aziraphale stopped and decided that he didn't want to know.
"So did you?" Crowley asked, a little worried. "Drain it, I mean."
"I tried," Aziraphale said, grimacing. "It grabbed me." He shuddered. Crowley brightened.
"Really? That's…" The look the angel gave him was venomous. Crowley shut his mouth, looking sheepish. "…sorry."
"It has tentacles."
Crowley said nothing, though it looked as though it were taking effort not to.
"His name's Adolf."
"Adolf as in Hitler?"
"It's kind of a joke," Crowley said defensively.
Aziraphale hiked up the slipping towel. "And it has a name?"
The demon did have the grace to look sheepish.
"Where did it come from, anyway?"
Aziraphale stared at him. "You mean to tell me that there's a tentacle monster living in your bathtub and you don't know how it got there?"
"It just sort of…appeared."
"…and you haven't done anything about it? What do you think it is, some kind of pet?"
There was a highly suspicious silence. Aziraphale stared at Crowley in disbelief.
"You're losing your towel," Crowley pointed out sullenly.
Aziraphale hiked it up again, irritably, and opened his mouth, but was interrupted by a quiet burbling noise from the bathroom. Both of them turned to look at it.
"What was that?"
Crowley looked slightly concerned. "I'm not sure." He started toward the bathroom. Aziraphale stared at his back and then followed him. "Are you even thinking about this?" Crowley didn't answer. Aziraphale caught up to him standing next to the full bathtub and looking down at the water, which was swirling in a psychedelic, kaleidoscopic array of color. Aziraphale would have felt dizzy, had he been capable.
"What is that?"
"The color of insanity," Crowley said, seriously. Silence followed.
"You did not just-"
"Sorry," the demon apologized. "I don't know. He's never done that before."
"Stop that. Stop referring to it as a he. You'll get attached to it."
"I told you, his name is Adolf," Crowley said, "And,"
Again, the thing in the tub made a curious burbling noise and raised four tentacles out of the water, waving them in a manner that was vaguely plaintive.
"What does it want?" Aziraphale asked peevishly, readjusting his towel.
"I think he's hungry. What do tentacle monsters eat?"
Aziraphale threw up his hands. "Oh. Marvelous. Now you're feeding it?"
"I'm not going to just let him starve. What do they eat?"
"I don't know, souls of the damned," snarked Aziraphale. Crowley shot him a look.
"We could try mice," Crowley said thoughtfully.
"What, do you just have some mice lurking around in your freezer?"
"I was going to do something with them eventually." There was a bit of a silence. "…kidding, Aziraphale. I'll be right back."
"Try to be quick," Aziraphale said, irritably, wrapping the towel more securely and tucking in the end. "I don't think it likes me very much."
As though to prove his point, the thing in the tub burbled again. Aziraphale could almost hear it promising watery vengeance even as it drew the tentacles back underwater, the colors-of-insanity fading but the water still curiously opaque. Crowley returned a moment later holding a squirming little mouse by the tail. "Little bugger bit me," He commented.
"Poor you." Aziraphale took a step back. "Has it occurred to you that your bathtub might be an inter-dimensional portal?"
"You might think about the possibility."
Crowley eyed his friend, briefly. "I'll consider it." He dropped the mouse in the tub, without further ado. "Let's see how this works." Alarmingly, it sank.
"Interesting," the demon mused.
"Mm," said the angel noncommittally.
A few moments later came another little burble, sounding vaguely pleased this time, and then the mouse bobbed to the surface, whole and very much dead.
"Will you look at that," said Crowley. "It did work."
"It didn't eat it," Aziraphale said, wrinkling his nose.
"Seems to be happy about it, though." Crowley paused, then looked over the edge of the tub. "That right, Adolf?"
The tentacles came out of the water again, waved around a bit, hooked over the side of the tub, and tightened. With an odd squelching noise, something emerged from the water, clinging to the side of the tub by its many tentacles.
It looked like an octopus. Sort of. Except that it was unfolding tiny, membranous wings from its bulbous body. The eyes glowed an eerie red. The skin pulsed slightly in a vaguely nauseating manner and was colored an oddly sickly green. The pair stared at it.
It mewed, then burbled, blowing multicolored bubbles over the bathroom. One hit Aziraphale's nose and popped. It smelled vaguely mousy.
"…h'lo, Adolf," Crowley said, sounding a little surprised. The tentacle monster mewed again, and reached out one tentacle in Crowley's direction and it blorped, curiously. Aziraphale decided it was time to interfere. He seized the demon's arm and dragged him forcibly back out of the bathroom. And shut the door.
"What are you doing?" Crowley complained.
"Crowley. There is. A tentacle monster. In your bathtub. It has glowing red eyes and pea soup colored skin."
"Do you not see anything wrong with this?"
"Not really." Crowley frowned. "Listen, he's burbling again."
"It's not a he. It's not even Earthly. It's a tentacle monster!"
Crowley frowned. "Aziraphale, it's my bathtub."
The door creaked. Both of them looked back. Adolf the tentacle monster mewed again, still dangling from the doorknob by his tentacles, little wings spread and flapping ineffectually.
"And look how smart he is! He's already figured out the doorknob."
"Crowley, you cannot keep a tentacle monster in the bathtub of your flat."
Aziraphale stared. "Because you can't!"
"What've you got against Adolf, anyway?" Crowley wanted to know. Aziraphale gaped more.
"…Crowley. A tentacle monster. That makes colors-of-insanity in your bathtub and apparently devours the souls of mice only to burp multicolored bubbles."
"I think he's cute."
They both turned to look at the dangling, unearthly horror, who removed one tentacle and waved it with a plaintive burble. The eyes glowed crimson. It pulsed once or twice, skin glistening with suspicious moisture. Crowley frowned.
"Adolf, you'll dry out. Get back in the tub."
It dropped to the floor and crawled across the floor, leaving a trail of noisome slime, to plop messily back into the bathtub. Aziraphale…just…stared.
"I think he wants some more mice," Crowley declared, authoritatively, and started off for the kitchen. Aziraphale looked at the stinking slime on the bathroom floor, at the glowing red eyes peering at him balefully over the edge of the tub, and could only find one word.