Ghost Biology

The following speculations are based on the assumptions that. . .

1. Evolution and biology work pretty much exactly as we know it.
2. Ghosts are real, and they can affect the world (perform work on a system).
3. Ghosts can act on the world by possession (which doesn't take any energy, since apparently it's just supplanting whatever your soul normally does) and acting on objects (which takes energy but I guess it's powered by soul power which is not infinite).
4. Ghosts are formed by things that die with unfinished work (defined by thought, defined in turn by instincts.
5. Genes can influence instincts.
6. Therefore, genes can strongly influence how likely a species is to become a ghost after death, as well as what it's instinctual behavior will be once it is.

Basically, how do you know that your pet hamster doesn't have SERIOUS BUSINESS at the time of it's death, and that SERIOUS BUSINESS is to fly around and scare hawks?

For the sake of sanity, I'm going to assume that a ghost becomes incoherent over several thousand years, and whatever ghostly consciousness remains eventually disperses like the heat from a torch.  It never disappear fully, but eventually it becomes spread thin.  Otherwise we'll reach some sort of ghost apocalypse where we have an arbitrarily large population of ghosts throwing everything around at once.

Of course, this carries an implication, too.  Just as the universe will one day suffer it's inevitable heat death, so will all space eventually be suffused with the haze of homogenous, sub-conscious ghost minds.

But that's outside the scope of this thought experiment.  This is mostly about the evolutionary impact that ghosts would have.

this kind of evolution.
wait, not this kind of evolution

Afterlife
The afterlife is probably full of babies and old people who are hideously racist, sexist, and just ignorant as all hell.  I'll say nothing further on the matter.

<brainstorming>

Ghost wolves

• Ancestral wolf-ghosts hunt alongside living wolves.  Half of the pack is ghost-wolves.
• Wolves treat ghost-wolves the same as real wolves.
• Ancestral wolf-ghosts can guide the pack to herd.
• Ancestral wolf-ghosts can assist the wolves by killing things.  (Metal as fuck.)
• Ancestral wolf-ghosts instinctual avoid become the alphas, 'cuz if they're the ones going around humping all the lady-wolves, there aren't going to be any babies.  Regardless, this probably still happens once in a while, and then the pack goes extinct.
• When the pack dies out, the ghost pack persists.
• Ghost wolf bones are powerful instruments, shamans love 'em.  How do you kill a ghost wolf and make his bones into a flute?  If ghosts can make parts of their bodies corporeal, then so can shaman spells.  
• Ghost bone armor?  Ghost wolf cloaks?  I imagine them looking a lot like their mundane counterparts.  Probably vulnerable to dispel, though.

Ectogor

• Living creature is attached to all of the ghosts of it's ancestors, which carry it around and act as tentacles.
• Like Baron Harkonnen.  Fat, hungry, and floating.
• Pretty much just a mouth, a gullet, and the appropriate gonads.  It's ancestor's ghosts are it's appendages.  Grandma is an ecto-arm, grandpa is an ecto-leg.
• Just a machine for turning food into offspring.  Probably gives birth to large, developed offspring (instead of millions of undeveloped babies, for example) because you don't want the number of living ectogors to outstrip the supply of dead ancestors.  
• But maybe not?  You could just have a bunch of little ghost-tentacles to reflect the high rate of juvenile mortality?
• How about this: after it dies, it metamorphoses into a tentacle thing.  Then the tentacle-thing continues to serve its offspring for many generations.
• What environment does it live in?  Can ghosts insulate a creature?  Protect it from the cold?  Could it capture water and hydrate it?  Could it assist in the dispersal/fusion of gametes?

Incubi and Succubi

• Incubism and Succubism are the same thing.
• Incubism and Succubism are caused by mutations in the INC7B gene.
• After death, the gene causes the manifestation of the organism's ghost with new, powerful behavioral compulsions: to spread the INC7B gene by ensuring the reproductive success of offspring and relatives (who are likely to also be carrying the INC7B gene).
• The ghost's mind is hijacked.  It no longer remembers who it was.
• The ghost manifests itself to living, male relatives and offspring as a female spirit, fucks them, and then runs away with the semen.
• Then, the ghost manifests itself to unrelated, living females as a male spirit, fucks them, and hopefully gets them pregnant.
• (Holy Shit.  This is probably the most biologically 'possible' thing on this page.  It makes sense as something that would evolve given our starting assumptions and it doesn't rely on ghosts doing a lot of work, since all it's really doing is transporting a few grams of semen around.)
• (Also, when the mindless ghost of a grandfather rapes his grandson and uses the sperm to impregnate all of the ladies around town, you know you have a beautifully fucked up incarnation of speculative ectobiology.)
• The manifestation of the INC7B phenotype is probably a very rare event, even in organisms that have the gene (recessive makes more sense).  So even in families that have the INC7B gene, you probably only have incubi/succubi every ten generations or something.
• In a way, your fucked up grandpa-ghost is working in your favor, trying to get you laid.
• Does the incubus discriminate?  Does it have a preference for depositing your sperm in younger, more fertile specimens?  Does it target wealthier daughters of merchants and aristocracy, in order to have children that are given more advantages in life?
• Basically, if you are visited by a succubus, you know that one of your relatives is the succubus, and can possibly take steps to lay the spirit to rest (probably going to involve defiling a tomb), which sounds like maybe an adventure hook.
• Of course, there are a lot of guys who wouldn't care.  They can be smelly, disgusting slobs who never leave their house and still get to have awesome ghost-sex.  Who cares if a lot of the children in town look like you?  (Possibly another adventure hook: find out why half the children in town look like that disgusting slob who never leaves his house.)

like this, except I guess it's actually your grandpa

Revenant Gazelles

• While they're alive, they're just like normal gazelles.
• If they are killed by violence, however, the ghost will animate the corpse (either immediately or a couple hours later, when it's been beheaded, skinned, and is roasting on the fire).
• The animate corpse of the gazelle will then attack its murderer with otherworldly strength.  It goes from being a prey animal to being a murder machine of the highest caliber.
• This is an effective discouragement from predation.
• Would this work in a game?  "Okay so you're roasting the gazelle over your campfire but then it comes alive, seemingly for no reason, and then tries to kill you."  Even if the laughing caravan guards explain your mistake at the next village, it still feels a little cheap.
• Might function better as a tool in the hand of PCs, rather than a gotcha.

Timeshare Humans

• What happens when a person is born without  a soul?  Presumably they still have a mind, since all the physical hardware is there.
• Fuck that line of thought.  I don't want to speculate on the nature of the mind:soul interface.

Timeshare Humans, pt 2

• Assuming that soul==mind: sometimes a person is just born without a soul.
• Basically, they're born into a coma.
• They're also easy vessels for possession.
• We have to assume that the unseen world has a harsh and violent ecology of its.  There are many unseen things, all around us, that would love to crawl into the skull of an empty human and settle down.
• When one of these things notices this unoccupied baby, it will slip inside.
• So now we have people growing up with a completely alien intelligence inside of them.
• It could be a ghost.
• It could be angel or a demon.
• It could be a machine intelligence from another dimension.
• It could be a hydrogen core metamind distributed across the stars.  It could be a constellation.
• It could be the fucking spirit of Hercules.
• Assume that there is a time limit on this, say d6+12 years, after which the meat becomes hostile to the mind and evicts it.  The body lapses into another coma, and will remain there unless another soul comes to claim it.
• These empty vessels would be worth a lot on the blackest of black markets.  Sort of like how hackers can surreptitiously gain control of thousands of people's home computers (a botnet) and then sell them off to the highest bidder.
• In this way, a human body could live a long, full life without ever really living.  It would be inhabited by extraplanar forces, demonic squatters, and disembodied intelligences from exoplanets whose cities have long since gone dark.

Zondervoze

• So the cells in your brain are like little animals.  They eat, sleep, reproduce, and recover from injury.  They can react to stimulus.  But, presumably, an individual brain cell is not home to a particular consciousness, because consciousness exists on a higher level.
• So the people in your city are like big animals.  They eat, sleep, reproduce, and recover from injury.  They can react to stimulus.  But, presumably, an individual person is not home to a distributed hyper-intelligence, because a distributed hyper-intelligence exists on a higher level.
• That's what a Zondervoze is.  Brain cell : human :: human : zondervoze.  A zondervoze is built from the minds of it's constituent people and the communications between them.
• Communication is key.  Emergent complexity.
• It's a zeitgeist.  It's the soul of a generation.  It's the heart of a city.  It's teen spirit.
• It doesn't exist as a creature outside of the humans that generate it, just as your mind doesn't exist outside of the neurons that generate it.
• If humans are the neurons, then what are it's muscles?  It's arms and legs?  Buildings?  Ships?  Firepits?  Memes?
• The boundaries could be shaky (are all of your neurons connected all of the time?) but the distributed hyper-consciousness acts like a singular intelligence.  It thinks it is a singular intelligence.  It feels like a singular intelligence.
• Big cities could have several different zondervoze within it, each grappling for power against the others.  What you see as class warfare is actually one zondervoze choking the life out of another.  What you see as a clash of cultures is actually one mimetic super-organism devouring another.
• Maybe the PCs are investing the murder of several high-profile leaders in the immigrant district.  The murders appear to have unlinked motives--jealously, unpaid debts, drunken rage--but the timing and specificity seems to be too much of a coincidence.  Their only lead, a raving madman who spoke about the "voice of voices" and "destiny of the white man" was just killed in prison when he accidentally spilled a psychopaths cup of milk.  Again, too much coincidence.
• Maybe they are in a crowded marketplace, discussing the clues.
• Maybe a pair of philosophers walk past, and the party overhears one of them say to the other, ". . . because you ask too many questions. . ."
• And then a mother stops her son from eating dirt and the party overhears ". . . so don't do that.  It makes me upset. . ."
• And then a pair of squires walk past, and the party overhears " . . .get the message?  I worried that you won't get the message. . ."
• And then a pair of blacksmiths at another table fly into a rage over some insult, and one shouts, "If you keep that up, I'll KILL YOU!  I swear on my mum's grave, I will MURDER YOU."
• And if the PCs question any of these people, they will receive only confused looks in return.
• It's enough to drive someone mad.
• It's also a good way to die under unfortunate coincidences.

• Another scene.
• The PCs just stumbled into a pack of thieves who accidentally killed a nobleman they were trying to rob.  Now that the PCs have seen them, the thieves were forced to try to kill the PCs, to ensure there were no witnesses.  It was messy battle.  The thieves were disguised as foresters, and had axes.
• One PC says, "Well, that was an unfortunate coincidence.  I expect we'll never be that unlucky again."
• The PCs are interrupted by the sound of laughter.  Two drunks stumble out of a bar, supporting each other and waving mugs of beer.  "Ahahahahaha!" shouts one.  "Are you serious?  I could do this all night!"

Ghost Mecha

• I guess if you're a mecha pilot your whole life and then you die, they might decide that you're valuable enough, and then they build you a tomb mecha, which houses your physical remains and binds your spirit to the CPU.
• Possibly a nice twist for a party that thinks that they have finally defeated their rival, some asshole pilot ace from the necro-arcologies.
• On a different line of thought, can you exploit ghosts?  Instead of spending billions developing an unstable AI, why not just dig up some Native American burial ground, raise the ghosts, and then trick the warrior spirits into piloting your new megaton tank?

Ancestral Shells

• Same thing as above, except maybe elves use them to store their ancestors.
• Like a graveyard, except the tombstones will all animate if you fuck around.
• Maybe the tombstones are logs, or scarecrows, or weapons, or wooden golems.
• Some are used for war, some are used for wisdom.
• Starcraft had something sorta like this.
• Maybe make it pseudo-egyption?  Hawk-headed clay golem with a mummy inside?  Or maybe just a bunch of canopic jars containing organs?  Maybe all golems are like this.
• Inside every iron golem is the charred skeleton of the person who was sacrificed during when the metal was poured during casting.

Ectoplasmic Biology

• Are there things that eat ghosts?
• Can vegetarians eat ghosts?
• If ghosts can form new memories, what if they joined a new religion after their death?  And how does this affect their salvation?
• What else shares the unseen world with ghosts?
• Are the things in there that were never alive to begin with?

This model is not dependent on an afterlife to make "sense".  Good.  Fewer dependencies = easier to plug into other people's games + more freedom when writing.

</brainstorming>

I should write a Book of Ghosts.