"Ooo Oo oo o Ooo O o ooOOo o00o. Ooo OO o000", said Crowley.
"I'm sorry, what was that?"
Crowley blinked, then cleared his throat. More bubbles floated towards the surface.
"Sorry", he apologised, his voice now clearly audible. "Wasn't paying attention. I said: Well, this is a bit of a letdown, innit? Not much here."
"It's the bottom of the ocean", said Aziraphale. "I don't know what you expected."
The demon shrugged lopsidedly, the motion causing a small clump of dead phytoplankton trundling past to disperse in all directions and costing at least one deep sea creature its next meal. Most likely a sea cucumber, which were the only living things they had seen so far and which were bluntly speaking boring as Hell, at least in Crowley's opinion.
"Dunno", he said. "Atlantis maybe?"
The angel shook his head doubtfully.
"I don't think Adam kept it", he said.
"Hm. Yeah, probably not. Besides we're in the wrong part of the world for that."
"Oh well. At least we can say we've been there. Challenger Deep, Mariana Trench. Done."
Aziraphale lifted a hand and ticked off an imaginary checkbox with a cheerful smile. Being an angel meant that he of course loved all of the Almighty's creatures big and small equally, but privately he was inclined to agree with Crowley about the relative interestingness of some of them, although he had admittedly been quite impressed by the considerable size of some of the specimen they'd seen.
"Do you want to-", he began, then interrupted himself: "Oh! What's that over there?" He gestured excitedly at something behind Crowley. "Can't be a jellyfish this deep, can it?"
Crowley turned around to see what he was pointing at. It was small and white and...
It was a ragged plastic bag.
They stared at it.
"Never mind", said the angel.
They watched it float past silently for a moment. Aziraphale wondered if there were sea creatures that ate plastic yet. Probably not.
"Sagarmāthā next?"
"Sure", said Crowley. "But don't expect less rubbish."
Aziraphale sighed.
"Humans. Really."
"Should have done all this stuff before the invention of plastic", said Crowley sullenly. "Next time I see Pollution we're gonna have Words.