One of the winning entries in Bogleech.com's Creepypasta Cookoff 2013, Captain's Log is, Exactly What It Says on the Tin, a series of log entries by a space captain chronicling a centuries-long voyage to a newly discovered alien planet.
Notable for its clever, multi-layered Twist Ending, part of which you'll probably see coming a lightyear away, part of it, not so much. Beware of spoilers.
This story provides examples of:
- Alien Abduction: Being space explorers investigating an alien planet, the crew need to collect a few samples of the local life forms.
- Aliens Steal Cattle: The reason they keep mutilating cattle over and over? They think it's the same cow every time.
- The All-Concealing "I": You probably figured out from the start that the captain and his crew are aliens. Precisely what kind of aliens, though...
- Bizarre Alien Biology: Despite being Humanoid Aliens, from what little description we get, the Greys' physiology seems pretty damn alien (and probably physically impossible). Their eyeballs are so dark because they contain osmium where a human's uses zinc; their skin apparently doesn't secrete oil; they don't appear to even know what hair is and weirdest of all they don't have DNA. Their genetic material is some sort of base and they're genuinely shocked that Earth creatures' genes are acidic.
- Captain's Log: The entire story, natch. Though Captains' Log would be more accurate.
- Driven to Suicide: Several crew members decide to kill themselves rather than wait for their memories to run out, including the first captain.
- Easy Amnesia: Averted to hell and gone with its rather disturbing portrayal of anterrograde amnesia.
- Fate Worse than Death: Doing the same things over and over again because your brain has run out of memory.
- The Greys: This story shows how they came to be and why they always act the way they do.
- Gone Horribly Right: The nanomachines designed to keep the crew healthy work exactly as intended, healing every injury, curing every illness, even stopping the aging process. The problem is that nobody ever stopped to consider the long-term effects of functional immortality, for instance a person outliving their own capacity to form and store new memories.
- Healing Factor: Nanomachines have given this to everyone. After the crew gets bored with the books and videogames they have on the ship, they turn to torturing each other for fun, since they'll just recover from all injuries.
- Humans Through Alien Eyes: The Third Acting Captain finds humans so different despite their similar looks that they border on Eldritch Abominations.
- Immortality: Thanks to advanced medical Nano Machines, the entire crew are immortal, which is pretty handy when getting anywhere in space takes hundreds of years. Leads to some major Power Perversion Potential when they run out of things to do.
- "Just So" Story: And that's why we have the Greys abducting humans and mutilating cattle.
- No Name Given: None of the characters, or the ship for that matter, have names. Pretty typical of Creepypasta.
- Required Secondary Powers: A chilling example of what happens when these aren't taken into account.
- Space Madness: The crew starts going crazy after they run out of things to read.
- Time Abyss: By the end the crew have been abducting people and mutilating cattle for over 30,000 years, probably more.
- Universal Universe Time: In a workaround for this trope used by many harder sci-fi stories, the ship measures time in the orders of magnitude of seconds (kiloseconds, megaseconds, etc.) elapsed since the start of the voyage. That still doesn't explain the fact that the captain describes the travel time to Earth as around 300 years and the mission time count roughly matches up with that in Earth years despite them not being from Earth. Or that "seconds" is a pretty arbitrary measure of time that aliens probably wouldn't use. Could be another case of the Translation Convention.