Spook

IRL spook dealer, also demonstrating advanced effects of getting high on his own supply.

"Spook for the spook God!"

– Probably this motherfucker, associate of an infamous Slaaneshi warband but also alleged inquisitorial field agent.

Spook is a drug in the Warhammer 40k universe, in most fluff originating in Necromunda, the exact type of substance it is derived from being inconsistent, perhaps because the Orlocks don't want you to know—ranging from decayed corpse starch to a fungus growing, both found deep in the Underhive. It is highly illegal and generally considered to be a liability due to it's connection with the warp, from which it can either heighten psychedelic abilities to turn one into a thingamajig. It is nonetheless popular, however, both as a recreational drug and a tool for upping a wyrd's powerlevel (it can give a boost to unsanctioned psykers but at the cost of increased chance of things going very wrong.) It is found as a fungus, lichen, or powder (fluff isn't always clear), harvested somehow, and taken as liquid.

Low doses give users a feeling of connection to the universe, maaaan. Higher more dangerous doses are sometimes used by rogue psykers going into battle or as a part of cult rituals or generally in search of a deeper rape with the warp. This has a tendency to go wrong. Very wrong.

It seems that, while open usage might very well get the Inquisition involved given the risks, every strata of Necromundan society is permeated with the stuff. Lowly scavvies find it in the wild, underhive gangs (particularly those associated with the Orlocks, apparently) cultivate it on an organized basis, crime syndicates distribute it and ship it off world, hedonistic and indolent uphivers enjoy it's dubious pleasures, and even House Helmawr, rulers of Hive Primus and the very world itself, are rumored to be involved in the trade. Some of the distribution is run by Slaaneshi cultists, unsurprisingly.

Spook IRL

The latter bit of lore is not unlike the circumstances of psychedelics in the real world, except the cults of Slaanesh are just dirty hippies ... or so they want you to think.

Spook is generally thought of at least in the fandom as a sort of warp infused super-LSD or 'shrooms (both of which have an IRL connection to fungus) or DMT (which, even more than the other two, can make you feel as if you have warp powers, and all three can lead you to act batshit insane on occasion both acutely and chronically.)

Dangers

Spook, however, is pretty serious business as it runs the risk of, as IRL hippies would put it, allowing spiritual entities a way in to spread enlightenment in the hive. There is one story about a down-on-his-luck bounty hunter sent by a powerful ganger to whom he owes money to poison some "scavvy king"—unfortunately for him, the poison is spook, he has to partake, and winds up getting possessed for his trouble. At least he gets to RIP AND TEAR both the degenerate mutants and the gangers who were trying to put the squeeze on him for his trouble. But damn.

Users

Spook use is, however, as we mentioned, popular in all strata of Necromundan society, as it offers an escape from a bleak reality, if only for a little while. One assumes the quality of the spook involved varies from uphive to downhive. Whether this alters the risks of becoming an, uh, flibertigibbet daemon chow or playing host to a warp being who lets you explore your newfound powers before raping your soul to death is unclear, but it probably does.

Spook is said to be exported throughout the Imperium but it's prevalence very likely varies depending on place and time. Use in the Guard would probably result in summary execution. Using it during warp transit is probably a really, really bad idea.

Dominique, of TTS fame, despite being an inquisitorial scribe, apparently indulged, comparing a surreal situation do "doing the spook."

Various cults, not just Slaaneshi hedonists, but Tzeentch-worshipping sorcerers looking for a power boost, too. Doesn't seem like the kind of thing Khorne (who's too straightforward for trippy shit, plus there's some shit literally named Slaught and too many combat stimms to name) or Nurgle (too apathetic, he's probably more of an obscura type guy.)

Probably Cultist-chan. She wants to hang out and thripp owwt whith yhoo for kay-oss.

See Also

• Drugs
• There are a number of other warp-infused drugs going around, including flects, which play a key plot point in the Ravenor books while the titular inquisitor is running around playing DEA agent for a while, and the similar but distinct and seemingly milder gladstones.
• Icrotic slime is another Necromundan narcotic drug which is apparently actually some sort of brain eating amoeba that beyond some point of no return will basically reduce you into a zombie, and you'll be too blissed out to unplug. Grimdark. Better bring a friend to remove the gelatinous blob from your head in time. Apparently up in the Spire there are drugs that can counteract this and let the uphivers go sliming without the risk. Whether this actually has to do directly with chaos is left unsaid but it probably does.