Real world economics: money is a rare and desired commodity (or a stand-in for such a commodity). There is generally a semi-fixed amount of it, and if it is not "in circulation", it is at least somewhere that something intelligent and actively interested in that value put it, lost it, or abandoned it.
Not so in videogames. For many game economies, wealth is apparently associated with dangerous creatures. To wit: if you can attack it and it is alive (in some sense) and/or able to theoretically attack in return, it probably has some actual currency which will become available upon its death. This will be true almost without regard for the creature's ability to carry money, its interest in money, whether it's sentient enough to comprehend money, or any connection with the existence of the money. On occasion, this is true regardless of whether it had money the first time.
Occasionally, there will be an in-game Hand Wave saying that there's a bounty on the monsters you're fighting. However, unless there's a specific sub-quest requiring you to, say, slay twenty bears and bring back their asses, you will never be required to talk to a specific person or prove that you've killed the monsters in order to get the money. Vendor Trash is sometimes used as more realistic version - killing the monsters doesn't get you immediate money, but you can easily sell their teeth, hides, or feathers back in town. However, this eats up precious seconds of a player's time, in which time you might get bored and switch to another game. And we can't have that, now can we?
Named for the spiders in the family Lynyphiidae, called "money spiders" in the UK from the superstition that they are associated with wealth. Ironically in light of the trope, these spiders are supposed to be left unharmed in order to become richer.
While having a danger-based currency is rather plausible (for certain values of plausible) — after all, currency stands for commodities (goods or services) or labor, and killing a dangerous creature is not only a useful service, especially in a monster-filled world, but can indeed be quite a bit of labor — this has largely become a Discredited Trope, to the point that reviewers occasionally bash game developers for making monsters drop money.
Parodied in a great number of video-game-based webcomics and other satire. Not to be confused with this. Nor this.◊ For a specific enemy that you seek out because it carries a lot of money (or other reward), see Piñata Enemy, with tougher variants being Metal Slimes. For the general case of monsters dropping implausible items, see Impossible Item Drop.
Note that even if a game uses this type of system, it may not mean that the monsters are actually dropping money. It could be that the monsters are dropping stuff like pelts, fangs, claws, whatever you'd expect, and the amount of "money" you claim is actually just what the drops are worth. In this case, purchasing items is less paying money for them, and more bartering your monster drops for them. It's just streamlined to you getting the money directly instead of having to sell the items either because the programmers don't think the players could handle it, or because the necessary level of micromanagement would detract from the fun for most players.
Played totally straight with Dragons. Dragons carry lots of treasure on their naked bodies. This is explained as them taking Scrooge McDuck-style money-baths in their hordes with coins and treasure getting stuck in their scales.
In at least one edition of AD&D, it was stated that the treasure values given were only for monsters encountered in their lair. DMs were expected to give nothing, or some appropriately small amount, for wandering monsters. This rule tended to be ignored.
Later editions at least try to encourage DMs to only put equipment on enemies if it would make sense for them to have them. Some tricks include keeping tally of the encounters the players have completed, and then having the players find the accumulated "loot" at an appropriate juncture (in the monsters' lair, for instance).
In 3.5, this trope is, though in effect, subverted in some instances. While many monsters do collect varying amounts treasure, wild animals and monsters with designs that would prevent them from acquiring loot in some way (such as not having opposable thumbs, or having incorporeal bodies or low intelligence scores) are listed as being incapable of carrying treasure at all.
The original intent was for money and magic to be the goal. Characters improved through collection of Experience Points, but monsters were worth quite little XP. Their treasures were worth 1 XP per Gold Piece, which amounted to much more XP value (plus of course you get the gold). So your goal was to fight as little as possible while trying to find money. Wandering monsters didn't carry treasure. Do you keep all your money in your wallet? But a lair contained treasure even if the monster was out. So avoiding wandering monsters was imperative since they were just a dangerous waste of time. And since wandering monsters had a chance of coming at regular intervals, they were effectively a penalty for wasting time. More efficient, skillful players were more successful even if their characters weren't all that hot.
Actually somewhat averted in D&D's fourth edition. While the player characters' income is definitely still meant to come from treasure to the point that there are standard expected rewards per level (with the actual economy of the game world, such as it is, being run strictly by NPCs in the background — there are no official "money-making" skills as such anymore and used gear and common items can only be sold at bargain prices, never anywhere near market value let alone for profit), those treasures are not linked to specific creatures or encounters anymore. So a party of five first-level characters may be able to expect about four magic items plus 720 gold pieces' worth of "monetary" treasure total, give or take, in the course of advancing to second level; but the placement of said treasures (in the common hoard of a bunch of monsters, abandoned in some dungeon, as a reward by quest givers or even actually dropped by magical spiders if desired) is wholly up to the DM.
A common practice amongst DMs is to place all of the treasure at a logical point in the adventure, such as in a monster's lair, or as a bounty. In situations where massive piles of gold are impractical, a DM might place a piece of Vendor Trash amongst the loot, worth the amount of currency expected.
One technique to allow loot for wandering non-humanoid monsters that would swallow prey whole (giant lizards, crocodiles, sharks, etc.) would be to have the treasure in the creature's stomach. This is why many old school roleplayers will slit a creature's stomach in their search for treasure.
A pretty obscure example: In the classic 1993 dungeon crawler Warhammer Quest by Games Workshop, the first scenario of the campaign features a well from which an infinite number of spiders crawl out of, each one giving a small amount of gold to the one who has slain it. If the dungeon master doesn't step in at this point, it's possible for players to accumulate an infinite amount of gold.
Video Games — 4 X
In Civilization 4, the Great Merchants, when fulfilling their player-chosen purpose in a city tile, express this action by jumping up in the air and literally exploding into gold coins.
And in Civilization 5, a doctrine allow you to earn gold coin by destroying barbarian and enemy units.
Video Games — Action Adventure
The Legend of Zelda: A Link to the Past has literal Money Spiders. Throughout Hyrule, some rocks have spiders underneath that, when freed, start dropping money. It's actually best to not kill them; after a while, the value of the rupees increases until it disappears by itself.
The Legend of Zelda: Ocarina of Time has Big Skulltulas and Skullwalltulas, which occasionally drop money upon death, but it also has Gold Skulltulas, which don't drop money directly; instead, they drop tokens. As you collect these tokens, a cursed family taking the shape of Skulltulas with semi-human features are freed from the curse one by one. When all of the tokens have been collected, the father will give you 200 rupees if you talk to him. You can leave and come back in and he will continue to reward you as long as you want.
Also in Ocarina of Time are Poes. They can be stored in bottles upon defeat, and can then be sold to an old lady in the Marketplace (or at least where the Marketplace used to be). Given it's the Poe's essence that's being collected, this can almost be called an Essence Drop.
The Legend Of Zelda Twilight Princess has a similar sidequest, except instead of gold-plated spiders that just sit there, you need to use your wolf senses to find and defeat Imp Poes that actually fight, and the victim of the curse has been transformed into a golden statue.
The original NES version has Ropes, snake enemies that almost always drop blue rupees when defeated.
The Castlevania games have not only monsters dropping money, but candles, chandeliers, and other fixtures. Super Castlevania 4 actually features a boss called the Zapft Bat, which made entirely out of coins and jewels.
Enemies in La-Mulana will often leave behind coins or some type of ammo.
In The Guardian Legend, enemies will sometimes drop Power Chips, which function as both money and ammo.
Luigis Mansion has gold mice that are worth a LOT of money if sucked up. In Luigi's Mansion: Dark Moon, gold mice, as well as gold bats, beetles, and (yes) spiders, net a gold bar or several bills if flashed with the Spectrobe. The regular versions of these enemies will drop coins or hearts. Speedy Spirits (in 1) Gold Greenies in (''Dark Moon') will drop tons of money if sucked up.
Video Games — Action Game
In Nightmare Before Christmas Oogies Revenge, there are literal money spiders that attempt to steal Jack Skellington's Souls, the Halloween Town equivalent of money. They can then run off with it and you'll never get it back again. Every enemy in the game drops Souls as well, but they can also randomly drop the Green Soul health item, the Blue Soul power-up item, or the Red Soul item, which is ammo for Jack's fire-breathing pumpkin form. Confused yet?
Monsters in Devil May Cry drop red orbs that are used as currency. That's reasonable enough, but so do chairs, statues and other inanimate objects. Obviously they're Tsukumogami hoping to avoid Dante's wrath by pretending to still be inanimate. It's the only way to explain them dropping crystallized demon blood.
Similarly, the angels of Bayonetta all drop "halos", golden rings that are used as a currency in Hell. As with Devil May Cry, various objects like statues, business signs or benches contain them too.
Justified in River City Ransom, an old school Nintendo Hard game, since when you beat people up they drop cash. In effect you are practically mugging them.
Video Games — Adventure Game
In Sam and Max: Reality 2.0, defeating a blue slime monster in the eponymous VR game yields... blue slime, which is simply used to solve a puzzle.
Team Fortress 2 does this through the ambiguous state of ammo; regardless of your weapon, you can pick up a dead player's weapon for a large refill of ammo (e.g. a bow and arrow wielding sniper will gain the same amount of the correct ammo regardless of if he picks up a filled minigun, an almost empty shotgun or a melee weapon). Note that this also extends in a more complex fashion to the Spy and Engineer; picking up those dropped weapons will give an additional reward of recharging your invisibility watch or giving more building currency (metal) to the respective classes.
Enemies in Heretic drop ammunition that sometimes seems completely at odds with the enemy that dropped it; i.e. the Sabreclaws attack only in melee, but drop ammo for the Hellstaff (think Plasma Rifle from Doom); the Undead Warriors throw axes at you but drop arrows for the Ethereal Crossbow, etc.
Borderlands, where everything drops either wads of cash, health vials, ammo or all sorts of guns. Partially handwaved as skags and probably most other monsters eat anything but yak up anything they can't digest. Makes you wonder how a scag pup can eat a whole sniper rifle. Also averted with the bounty board sidequests. Sent out to kill a specific enemy? It has a bounty due to it's danger to other humans.
In Borderlands2, the enemies known as Crystalisks are large three-legged stone creatures that have crystal clusters on their legs and main body. Destroying these clusters is the fastest way to dispatch them (they can be destroyed with a single melee attack) and each cluster explodes into crystals that can be picked up for money. When all of the clusters are gone, they further explode into more money crystals. In a mission where you collect audio logs, you find out that it was because of their Money Spider status that they became hostile to humans. Initially docile, the Dahl corporation began mining them to the disagreement of a security officer who befriended them and died trying to protect them. Eventually this led to the Crystalisks becoming completely hostile towards humanity and severely biting the humans in the ass.
Video Games — Hack and Slash
Diablo. Justified, as the first game manual states that demons like to hoard wealth despite having no apparent use for it.
A very thin justification, since one wonders where Dem Bones are keeping the money that falls out of them when they get killed.
It's even better when you kill a swarm of thousands of tiny insects (with 3 ordinary arrows) and they drop a suit of armor.
Diablo III introduces the Treasure Demon, a devious little goblin that likes to rob merchants and drop lots of gold. If you don't kill it fast enough, it'll open a portal to only the angels know where and disappear on you, but if you manage to kill it, it drops lots of magical stuff.
Video Games — MMORP Gs
Spoofyfied in the MMORPG Kingdom Of Loathing, where the unit of currency is meat, and things like gold and jewels are useless, except as Vendor Trash; thus, converting a giant rat into a giant rat carcass makes a twisted kind of financial sense. Some characters not made of meat (e.g. the robotic Magi Mech TechMecha Mech) drop no meat in a zone with otherwise high meat drops. Some thematically rich monsters (e.g. the Wealthy Pirate) drop more meat than other monsters in the same zone, and hippies of all stripes (except the Business Hippy) drop no meat. But at that same time, they fall for this trope in an even more nonsensical way; pretty much everything drops meat, so while it makes sense for animals and other creatures to drop meat, some things have no reason to have meat, like the possessed vegetables.
Ghost miners don't drop any meat. Nor do other ghosts, skeletons, the El Vibrato mechanical constructs, paper towelgeists, any of the nightstands in Lord Spookyraven's bedroom (though some do have wallets and coin purses), the constellations... the possessed cans of tomatoes and asparagus do, but far more often than not, monsters not made of meat (and hippies) don't drop meat, unless they have some thematic reason to carry it. Size also matters. Rotund ducks drop more meat than the other types of duck, and the most efficient place to farm for meat is The Castle In The Clouds In The Sky, which is inhabited by giants.
EVE Onlinejustifies this almost completely - killing pirates produces a reward from the NPC police agency, and since it's a sci-fi setting, the lack of going back to them in person is reasonable. As well, the loot tables are designed such that enemies will only ever drop things that they could reasonably have. Of course, there's no difference in combat power between enemies with vendor trash guns and enemies with rare drop guns, but it's still better than most.
The browser-based MMORPG Improbable Island justifies this. The requisition tokens are dispensed from the cameras filming the war (It's a war... but it's also reality TV!).
While some of the animals and creatures in RuneScape drop what they usually do (like bones and meat), many other creatures drop coins, runes and other equipment.
Final Fantasy XI only has beastmen drop gil, and even then in pitiful amounts. However, all creatures (including those that drop gil) have a chance of dropping items befitting the creature (beehive chips on bees, for example) and if the player has the "Signet" effect active the creature will also drop elemental crystals, a requirement for crafting. Typically the random items will be useful for crafting only with some exceptions that are quest items or equipment. Gil is also dropped by certain Notorious Monsters and undead (specifically, Fomors and qutrubs; justified in that the former are the undead closest to the living and the latter are supposed to beattracted to shiny objects).
In the MMORPG Tabula Rasa you get credits for every enemy you kill but you don't pick them up- you're automatically credited to your account as a bounty by high command (since you're part of a giant army credits aren't strictly speaking a currency, they're an equipment requisition resource). Additionally, most enemies drop Vendor Trash which up until recently were only good to be "sold" for more credits, although a lot of them can now be broken down for crafting resource.
Dream Of Mirror Online only allows you to acquire gold via Elder quests and pawning things off. Fortunately, monsters can drop tools (like arrows), medicinal items (like beans), alchemical materials, Elder quest items, and coupons, all of which can be traded in at vendors and the Recycling Bros. for money; in fact, coupons have no purpose other than to be traded in to the Banker for cold hard cash. 100 spaces (50 on hand + 50 bank) is, predictably, never enough.
Runes Of Magic has you primarily earning gold from doing regular and daily quests, as well as selling off any drops that you find off mobs you kill. Mobs do not drop gold like in other games, but they do drop daily quest items, health or mana potions, the occasional weapon or piece of armor that you can use or sell off, and ranged weapon ammunition and crafting skill recipes, which are not sellable to NPCs, meaning you have to either get rid of them or sell them off on the Auction House if you can't use them or don't want them.
Justified: the ancient monster Glas Ghaibhleann ate gold, and monsters took to carrying the stuff in case he became hungry and got cranky. He isn't around anymore, but maybe the monsters got into the habit.
Also in the Generation 2 Mainstream, the first of the final bosses, Tabhartas is made of the gold every single Paladin Trainee gave as a fee for training. Even the gold you gave. Although, this IS before Esras'Face Heel Turn/Reveal, so you don't suspect a thing until later on.
In MapleStory, sufficiently high level mobs will start dropping stacks of bills instead of shiny coins. You can also grind certain mobs for weapons and armor (usually then sold off as Vendor Trash).
Video Games — Platform Game
Justified in Wario World, as the enemies are treasure transformed into monsters by the Black Jewel.
In the Ratchet & Clank series, the main units of currency in the galaxy are Bolts. Naturally, there are a lot of them scattered around when a robotic enemy is defeated, but paradoxically organic monsters drop them too. However, since bolts are so ubiquitous, damn near everything gives up bolts when destroyed, even the scenery...
Super Mario Bros. Apparently, Bowser has not only enough money to spend on ridiculously complex castles that Mario will demolish with his passing, but in many games his minions carry at least one coin, which they relinquish if they're defeated with a fireball.
Tiny Castle initially plays this straight, then justifies it. The monsters eat metal, and the princess who owns them is so wealthy that she can afford to feed them coins.
In Mitsume Ga Tooru where everything tries to kill you, even the birds and spiders seem to carry large spinning coins with them.
Donkey Kong can earn coins by jumping on at least three enemies in succession in Donkey Kong Country Returns. If he jumps on eight at once, he gets an extra life.
Spoofed in the 2004 remake of The Bards Tale. Early in the game, the Bard kills a wolf and finds a vast hoard of treasure, much to the surprise and consternation of the narrator. The narrator decides that there will be no more random gems or treasure chests dropping of killed animals. The main character is upset about this but the enemy will still drop various loot instantly changed into money when you pick it up. These drops are very tongue-in-cheek in their nature; for example, enemy druids will drop miniature souvenir copies of Stonehenge, wolves can drop little red capes and hoods, and goblin-type enemies, called Trow, drop, among other things, leather pants. Dropping Trow indeed.
In Mega Man Legends, quantum refractor shards, tiny versions of the big crystals of Lost Technology that power things in the After the End setting, are the main form of currency. Naturally, the robotic Reaverbot enemies, found in hostile tunnels underground, spill them when destroyed. Those brave enough to go down into the tunnels and look for things have a built-in financial reward.
The Dragon Quest series has it with all monsters, although it makes sense with monsters like Goody Bags and Gold Golems, which are made of money in the first place.
Handwaved/justified in the anime series where it shows the Big Bad using gold and jewels as magical ingredients to create the monsters. Killing them just returns them to their natural state.
In the Metal Max series, and its sequel, Metal Saga, you get money by killing monsters. It's explicitly handled as being bounties on monsters, and handled more reasonably than most. Certain monsters become a special "target" for a short time, that gets you a bonus amount but needs to be turned in while it's still good; similarly, bosses come in the form of "Wanted" monsters that have especially high bounties — that also need to be turned in. You can also sell certain items dropped by monsters to bars as ingredients... although some of these are pretty unappetizing, like dirt from under monkeys' nails.
Phantasy Star IV is an example of the aforementioned Hand Wave, where Chaz and Alys are hunters whose job it is to eliminate dangerous monsters. Ironically, the most dangerous monster you can meet in a random encounter on the world map, the Sand Worm, gives you a ton of experience but only 1 meseta. It also has the Hunters' Guild, which allows the player to take commissions to kill specific monsters in some of the most (and least) interesting sidequests in 16-bit era RPGs.
In Kingdom Hearts, your primary means of earning Munny is killing heartless (and later, nobodies, too). Not only is it never explained how beings who are only interested in collecting hearts and lack flesh carry currency, but you are never in short supply after the very beginning of the game. Then again, in the PS2 games, you typically find better items in the field or at Synthesis shops anyway. 358/2 Days takes this to the absurd lengths of making it very easy to rack up hundreds of thousands of munny, while the most expensive items cost about 20,000, and you have no need for more than one. Ditto for heart points, Days' other currency, but that is Justified, due to collecting hearts being the Organization's primary objective in order to build Kingdom Hearts. Possibly justified in the case of Pot Spiders and Barrel Spiders, which were ordinary pots and barrels that contained munny before becoming Heartless.
Averted in EarthBound. The main character's (who is a small boy) father periodically deposits money to his bank account, which can be withdrawn from AT Ms. However, the amount of money deposited inexplicably corresponds to defeated enemies...
Averted in some of the Ultima series, especially parts V-VIII. Especially in the fifth game, killed animals can leave behind a mess of guts and blood, which when searched can sometimes yield a coin or two, with the implication being that it had been swallowed. In the ninth and final game, all enemies suddenly drop enormous piles of coins, which is one of the many reasons it is considered inferior to earlier games.
Averted in Neverwinter Nights 2 and the expansions, where killing a wolf will net you a wolf pelt, killing a person means they leave whatever they had on them, etc., etc. At the same time however, the same game plays this trope to a T. If the wolf doesn't drop a wolf pelt (or the person drop a person pelt), it will instead drop magical weapons and/or several thousand gold.
Storm of Zehir takes this even further. Sometimes enemies will drop truckloads of precious ores and timber that spawn in crates occasionally larger than the enemy that dropped it.
Dubloon awards you with dubloons every time you win a battle.
Justified in Slime Forest Adventure. The slimes are attracted to gold, and take it at every opportunity. The gold you get for defeating them is just the gold they took from someone else.
Somewhat less justified with the whales and sharks you fight.
The flash based web RPG Adventure Questpokes fun at this with the character "Robina Hood" who steals from the rich and gives to the monsters. "Because how did you think that spider got 5 gold?"
Its sister game, Dragon Fable, has Robina giving you a quest to knock out monsters and stick gold on them while they're unconscious.
Tales of the World: Radiant Mythology straddles the line between using this Hand Wave and not. Monsters do leave money, but it's generally trivial amounts—the real cash comes from completing quests and selling various items.
Brave Story: New Traveller uses monster-dropped Vendor Trash, and bounties on monsters that you actually do have to turn in... although you only have the former moneymaking option for a good chunk of the early game.
Lufia II had the main character start the game by walking into the item shop and apparently selling the corpses of the slimes he'd killed for the amount of money usually awarded for killing them. This included an argument when he was told the amount he could sell them for had gone down, because of how pervasive monsters had become as of late. The rest of the game just has money awarded at the end of battles, though.
The monsters in The Elder Scrolls III Morrowind usually drop potion ingredients. Most of them are cheap and selling them is almost useless, but some are rather valuable (such as cliff racer plumes or shalk resin), while others, such as dreugh wax (kill a dreugh) or Daedra's heart (kill a clannfear), can be sold for up to 200 drakes.
If you have the Alchemy skill, the potions that could be made from Daedra's heart were usually less valuable than the Daedra's heart itself, oddly enough. However, potions of levitation (especially good ones made with a high Alchemy skill) sold for a pretty penny, and could be made by mixing cliff racer plumes and trama root, both of which are mildly valuable but also rather common.
In The Elder Scrolls IV Oblivion, monsters rarely have gold, although many will yield an appropriate Alchemical component. Bandits and the like can be looted of their armor and weapons. Creatures have entirely understandable treasure on them. Strangely, looting the skin of a wolf or a bear leaves an entirely intact wolf/bear lying on the ground, despite what it should be missing.
In The Elder Scrolls V Skyrim most enemies have sensible drops (bandits have lock picks, Spriggans have nothing except their taproots) but occasionally wild animals have rare gems.
If you're lucky enough you can find two perfect rubies in the goat that lives in Falkreath. Meaning a goat could be richer than you in the game.
In the Fallout games the feral ghouls inexplicably carry bottle caps (the game's currency) and nothing else
In New Vegas the ghouls might also carry things like wrenches and packs of cigarettes. Might be explained by those items being personal effects before they turned into ghouls.
A particularly strange example in Dragon Age: Origins – Awakening are the children grubs. You watch them getting born from pods, presumably fresh from their mothers womb. Most of them are carrying minted gold, silver, and copper coins, conveniently in Ferelden's currency.
Wizardry: Proving Grounds of the Mad Overlord plays this trope straight, though it is justified when you encounter humanoid monsters, such as orcs, against groups of human enemies (of the same classes as your characters, such as ninjas, wizards, etc.), and against the one enemy whose corpse is currency, the Creeping Coin? (yes, the question mark is part of the name).
in Parasite Eve 2, Aya gains Bounty Points for every monster she defeats, which can be exchanged for various items and weapons.
Jade Empire has a very streamlined version where you don't even have to stop and pick up the money from the enemies you kill; it just automatically goes in your inventory.
Video Games — Simulation Game
Elite (the classic space combat/trading game that things like Wing Commander: Privateer were based on) had a particularly elegant implementation of the "bounty" system: when you vaporized a pirate ship, your computer simply sent a message and gun camera recording to the nearest starbase, and the bounty money was automatically deposited in your account. Privateer 2: The Darkening used a similar mechanism, though with bounties so low they didn't compensate for the endless waves of pirates that were a pain in the neck to avoid.
In Darkstar One, you're given credits every time you kill a pirate, or a member of a villainous gang (justified as a bounty).
Video Games — Survival Horror
Resident Evil 4 has a kind of money that makes sense and you mostly find it laying around or on corpses of humans or former humans. However, shooting the crows for some reason yields the best treasures you can get early on. Also, boss characters (such as the U3 in the shipping crates) carry immensely valuable bars of gold. What, did the rage-crazed beast figure it was a secure financial investment? In actuality, this trope probably applies less to the money and more to the ammunition for your weapons. You can snag ammo for all sorts of firearms from the villagers and other enemies who don't use guns at all. Perhaps the village had known that Leon was wandering around and decided to hide all the ammo for the lone shotgun in the upstairs bedroom but then why would they carry that ammo on their person? They even carry ammo for guns that can't be found anywhere but from the Merchant (such as TMP rounds). Plus you can do other weird things to restock your supply. Bird's nest? Shoot it down and have yourself a box of rifle ammo. Now we know what really happened to Kennedy...
The crows and bird nests may be justified. Stereotypically, they like to collect shiny objects.
In Dead Space practically every necromorph is carrying lots of cash or ammunition, which is largely sensible up until the zombie foetuses appear.
Video Games — Turn-Based Strategy
Most enemies in Final Fantasy Tactics A 2 drop "Loot" on death which can be sold for money or used for Item Crafting (although you do get money for completing the battle most of the time). Unlike other examples, the drops seem to be completely random, even though some items sound like they would come from a specific monster (Bomb Shell for example).
Yes, I know. I have no idea why these random animals are carrying 148 gil and a magic fire ring. It will forever be a 'mystery! - Narrator
Anime & Manga
In the RPG-esque Beet The Vandal Buster, characters kill monsters and then go to a special shop in the town, which reads their retinas to determine what monsters they have killed, in order to pay them for killing the monsters in addition to receiving a tattoo to signify "level".
Video Games — Adventure Game
Mostly averted in the Quest for Glory series. Humanoid creatures (and undead humanoids in QFG4) carry cash, although sometimes this isn't really justified (what are Croc-Men going to do with Tarna currency??). In addition, in most games earning money from combat is a slow arduous prospect, compared to things like completing quests, robbing houses and harvesting various magical ingredients. Also, some monsters have body parts that can be collected and sold for profit, but at least 1/3 of the random-encounter monsters in each game carry absolutely nothing. This includes some of the toughest ones like the Saurus Rex, Demon Worm and Necrotaur.
Lampshaded in free-or-subscribe flash game Adventure Quest, with a quest where you have to go around knocking out monsters and leaving gold on them. The quest explanation goes along the lines of 'Well how else did you think they got the gold?'
Video Games — First-Person Shooter
Inverted in S.T.A.L.K.E.R. series. Mutants have nothing on themselves but the occasionally body part in sidequests (mods also make them drop normally as Vendor Trash) and Stalkers carry weapons they use as well as ammo, comestibles and (sometimes) medicine. But even as they carry limited amount of money (so they can be sold stuff to) this money cannot be scavenged from their bodies, nor can their armor.
In Doom, zombies may drop either pistol ammo clips, or in the cases of shotgunners and chaingunners, their used weapons which hold limited ammo. Nothing else in the game drops anything at all when killed, though certain user-made game mods might change this.
Similarly, in the MMORPG Asherons Call, enemies often spawn with weapons that they are actually wielding against you. Mobs tend to drop specific types of items, for example, the little rat like monsters drop the occasional few coins, but also like to drop magical orbs (shiny objects), golems and undead tend to drop magical components, humanoid monsters tend to drop weapons, armor, and random food, etc. Most of the money in the game is made by selling randomly generated gear that drops to NPCs or other players.
Averted in the MMORPG City of Heroes, whose primary in-game currency is "Inf", which stands for Influence, Infamy, and Information. Heroes garner "Influence", which represents - literally - your ability to procure resources based solely on your reputation as a hero. Heroes wandering the streets of Paragon City will frequently come across villains randomly attacking ordinary citizens, who when rescued will come up to thank you - and you promptly gain a small amount of Influence. Villains receive Infamy as their form of Influence. However, Villains don't receive any extra infamy from citizens if they beat up the other Villain who was harassing the citizen. And Praetorians gather Information as their currency, as their world is such that you never truly know who is your friend and who is your enemy.
Partly explained in the MMORPG Dofus, you slay a giant sheep warlord for a key to a dungeon, if you fail the dungeon or want to try again one of the NPC's tells you to kill more monsters saying that the have eaten another adventurer, thus their key (And other possessions) are in the monsters belly. This doesn't explain though how one class has the ability to get more money and loot than all the other classes.
Sequel MMO Wakfu averts this with regard to actual specific money — "kama", the currency of the realm, must be minted by the players themselves using metal they mined themselves, and the only things to spend it on are A) items being sold by other players or B) rapid, convenient transit (you can get anywhere for free, but it takes longer). On the other hand, monsters still drop equipment, which could also theoretically be crafted; you're more likely to get the entire set a particular monster drops before you actually get enough ingredients to craft even one piece of said equipment.
Averted in aetolia. You can kill several creatures for money... but you have to find somebody whose put out a bounty on them and bring their corpses as proof of kill to get it.
Averted in The Lord of the Rings Online, where most monsters will not drop gold, but Vendor Trash like fur, tails, wings, etc. Only the races likely to use money (Humans, Dwarves, Orcs, Goblins, Uruk-hai and a few others) will drop money.
In Battlestar Galactica Online, most mooks only drop salvage that can be exchanged for currency, but sometimes you'll get actual stuff like Cubits.
Rather strong subversion in Dynasty Warriors Online in that NOBODY drops money at all. This would make a lot of sense because everybody is going to war, so there would be no reason to lug around money when you are about to fight, possibly to the death. Even if there was, giving the accumulated mass of war debris that would pile up, it would probably be hard to find. Instead all money is given through quests and at the end of certain timeframes, where you are paid for your part in the battle.
The one time people WOULD drop money would be treasure mode, where you have to bring caches of treasure to your base. As both sides are dropping it, it can be assumed that both armies were transporting their gold and using the opportunity to pick up more from the enemy.
Video Games — Roguelike
Angband averts this by use of monster tags, as only humanoid foes will have the DROP tag. One class of enemy, the creeping coins, may be a lampshade of this trope.
Many of it's variants go further, and have multiple types of DROP tag - Humanoid foes can drop armor, weapons, or coins. Dragons can multiples of the above, plus chests. Creeping coins can only drop coins. Etc.
Nothing at all drops money in Dwarf Fortress. In Fortress Mode, trade is done purely in barter, and the only way to obtain currency is to mint it yourself. In Adventurer Mode, coins can found stored in containers in bandit's camps or scattered around lairs of creatures who hoard them, and can be stolen without fighting the owners. Even then it's not too often a very large amount of money, and you'll probably get more selling the bandit's gear, gear of those who the monster killed before, and the monster's butchered corpse (assuming you can butcher it).
Video Games — Role-Playing Game
The Baldur's Gate series is fairly good at having actual money only on humanoid creatures. With non-humanoids you often had to be content with hides. Although finding diamonds on ghouls may seems a little odd, it is justified: Baldur's Gate is based on the old rules for Dungeons & Dragons. In said rules, in order to resurrect a corpse, part of the spell required that you replace the dead person's eyes with gems of a certain value. Later editions of the game had it such that the gems were consumed in the spell's casting.
In Baten Kaitos: Eternal Wings and the Lost Ocean, monsters don't drop money. Instead, you have to take pictures of them during battle, wait for the pictures to develop, then sell them. This was such a hassle that the sequel, Baten Kaitos Origins returned to the more traditional "monsters drop money" system, and it actually felt like an improvement. Unfortunately, there's very little worth buying in the sequel (unlike the first game, where ransacking every shop you come across is a good strategy), so the improvement goes unnoticed most of the time.
In EarthBound, Ness receives money from his dad instead of from monsters; the amount of money given, however, is a proportion of experience points won. This just leads to the question, how does dad know what monsters his son has killed, and where was this generosity early in the game?
In Fallout 3 and New Vegas, the wildlife doesn't carry anything other than its meat and/or body parts. Feral ghouls have odds and ends like bottle caps (the game's currency) or bobby pins because they were once humans who just got unlucky with a little radiation exposure. Enemies drop (and use) only what they have on them, or in the case of insects/robots, what they're made of. Human enemies will, however, pick up useful items they find lying around, which can lead to a particularly annoying case of a bandit happening across the best (unique) weapon in the game, and then vaporizing you with it out of the blue.
In Fallout 3, Super Mutant Behemoths (Fifty foot tall monsters carrying improvised clubs made from street lights) drop a ridiculous amount of loot when killed off. It could be handwaved by saying that the armor and guns the creature was carrying are actually from someone else, whom the Behemoth happened to eat. Regular Super Mutants and their ilk tend only to drop what they are carrying. Background info explains that the other Super Mutants use the (even less intelligent than they are) behemoths as pack mules, which partially explains the random assortment of junk.
In Fallout 2, animals never have any lootable gear of any kind. The major exception is after the player learns gecko skinning from a man in an early town; from then on dead geckos (a large post-nuclear mutant version of the tiny lizard, with a toxic golden variant) will have their pelt as an item on their corpse. They can be redeemed for cash from some buyers.
There is also the radscorpions in Fallout and Fallout 2, which drop their tails that can then be sold to certain vendors (it is used to make antidotes).
Fallout 1 and 2 were actually pretty good at this. Enemies were placed on the map with one or two weapons and a certain amount of ammo (which they are very willing to use) and perhaps some chems. If they run out of it (and you're still alive), they can't use it anymore, unlike Fallout 3's Bottomless Magazines. If they don't, you can loot what's left of it. Armor is invariably destroyed in the process.
In Pokemon, winning in random encounter will yield nothing more than experience. Money is received from other trainers (who would logically be carrying money). The amount of money won also differs based on the type of trainer. Swimmers and Bug Catchers reward little, as they don't carry much money. Gamblers, League officials, and elite trainers are loaded. Also works in reverse: You lose half your money when you lose, so the more you have, the more you risk. A certain item, the Amulet Coin, when equipped to a participating member of your party, will double the reward you get from an opposing Trainer.
However, one move (Pay Day) actually does yield money, even in random wild encounters. It's seldom used seriously, though, as the money gained is small and the attack itself is weak... The amount gained from Pay Day is equal to 2XY, with "X" being equal to the number of times the move was used, and "Y" equal to the user's level. With an Amulet Coin and a lot of patience, you can get (at least) 1000P per battle. Of course, the experience will be useless by that point (levels cap at 100), and holding the Amulet Coin means you can't steal items when using moves like Thief or Covet. There is a way around that, though complicated for the weak payout. Simply give the Amulet Coin to another Mon and switch them out for a round. Its effect on the battle remains. Plus the added benefit that it delays the leveling of the mon using Pay Day, by halving the XP with the monster subbed in.
Mostly averted in the first Xenosaga game, in which killing gnosis would never earn money, only item drops. Human enemies dropped money, while Mecha-Mooks gave up Scrap Metal as Vendor Trash. The second game did away with money altogether (except in one subquest in which objects could be sold to help out with someone's debt).
In Xenogears humans and mechs carry and subsequently drop money upon their defeat, but animals do not. Makes sense, since the mechs are piloted by people.
While Spiderweb's Exile/Avernum games (which pretty much all take place in a rather austere setting) are generally pretty good about relevant loot, the games go even further by noting that the nominal "gold" number referred to by merchants and the games' UI isn't really all gold, but instead mostly assorted rare commodities. However, processed metals are pretty damn rare in Avernum. You could make coins out of them. These games were also nice in that enemies are defined with items when they are spawned, will use the items they're holding, and on death will drop the items they're using. If a goblin spawns with a sword, he will use the sword to attack you, then when you kill it, there will be a sword lying on the ground in a puddle of goblin goo. Moreover, monsters will supposedly actually pick up and use items that they see lying on the ground. Exceptions are made for certain monster classes such as slimes, which are incapable of using or picking up items, but can still spawn with items and drop them when they die, like any other game.
Notably averted in Threads Of Fate, where after killing a monster it was said that you carried around their corpses until returning to the town, where they could be sold to a collector for cash. Oddly enough, this applied to the human enemies as well.
In The Witcher, gold and equipment can only be looted from humanoids, while monsters only drop alchemical components. There are a few extra tough monsters in the game that you can also loot a body part as a trophy from, then take to a certain NPC in the city to claim a reward for killing it.
Persona 3 has a bizarre variant on this. You do get money from running around dungeons killing things, but not from the monsters themselves. Instead, you get it from either treasure chests in the twisted, ever-changing, extra-dimensional random dungeon, or you pull it from some inner part of your mind if you pick the right randomly shuffled card at the end of some battles. Since all of this money is magically spawned from nowhere, and you buy all your weapons and armor under the table from a police officer, one wonders how come your character is never busted for counterfeiting.
And then there's the supernatural, extradimensional, metaphysical, quite possibly artificial Elizabeth pouring over 1 million yen in a fountain because she heard it's customary to drop coins in them. She probably got all that money from gouging previous adventures on Compendium buybacks, because she can also give you hefty monetary rewards for getting assorted debris from battles.
Persona 4 goes with the "Sell the crap you get from killing Shadows to the main store so you can get bigger and better equipment" approach. It's also played straight. Shadows drop money in addition to the Vendor Trash. Potentially handwaved in that shadows are the remnants of shadow-selves who killed their creators, and thus have their creators' possessions with them.
The first 4 .hack// games. Yes, a game based in — well, another game... an MMO to be precise — has you getting gold from not even humanoid enemies (they seem to be savage anyway), but solely from things that you sell.
Almost completely averted in Monster Hunter. You get most of your money from doing quests, and a comparatively small amount from selling random monster bits. However, said bits can also be crafted into weapons and armour; in fact, virtually all the high-level items are made from rare parts of fairly dangerous monsters, and a great many of them look like they are. Practically every drop in the game, outside of the special event quests like Arena quests, is something that would logically be found on the monster. Also, capturing said monster yields more components than outright killing it because you brought it back in (mostly) one piece.
Averted intentionally in Fable II. Enemies give loads of experience (which you can use to level up your character), but if you want the shiny-shiny, you'll have to get a job or go treasure hunting.
Averted in Siege Of Avalon, where the only enemies that give you money are the ones that have been looting the partly-ruined town for the last month or two. And only if you check their bodies. Oddly enough, the game never tells you how much each enemy has; you just seem to be magically gaining gold unless you're paying attention to your money before and after checking enemy corpses.
In the Mega Man Battle Network games, Money Spidering makes sense; since every enemy you fight is on the Internet, and the economy is Internet-based, it stands to reason that you'd reap an "instant cash reward" for virus busting or winning a battle against another Navi. (And there's plenty of Vendor Trash to be had, too — you can't SELL junk battlechips, but you can pop them into chip traders to try to get new, better chips.)
Partially averted in Star Ocean Till The End Of Time. Monsters drop money, but not much. The best way to acquire money is usually from opening chests in dungeons, though that is, of course, a finite source of cash. Arguably, spending your time creating and selling valuable items is an effective alternative to fighting monsters, which turns out to be a surprisingly realistic nod to real world artisan work.
In MouseHunt, the mice do not actually drop money, but every time you catch one the king rewards you for the bounty (a different amount is placed on ALL mice in the Kingdom). As for loot- some of them drop sensible loot (e.g. the Treant Mouse drops splintered wood) while others inexplicably drop loot that would make little sense (Bear mice dropping potions).
Beyond Good And Evil gets SO CLOSE to averting the trope... but then forgets to do so. The pearls you need for black-market goods are a Justified Trope, since the pearls actually seem to be Domz-based somehow (and it makes sense that they would therefore be expensive). And you can get money by photographing animals, because there is an ecologist (you only communicate with her by radio) who downloads the photos for her data collection. All of this would make perfect sense... but then, you kick a rat and money falls out. It's like they worked really hard to avert the trope, and then forgot they had done so and just played it straight.
Double averted in Final Fantasy The 4 Heroes Of Light. Monsters don't drop money at all — they drop gemstones, which can be used to upgrade your equipment or for Vendor Trash. All in all, the best way to make money is to exploit a shop-running minigame, not hunting monsters.
Averted in The Last Remnant; monsters never drop money, but there is a chance of being able to capture any killed monster. Captured monsters are apparently a delicacy, and can be sold directly to shops for cash.
Averted in Mass Effect 2, where killing anything will never get you any money. Even the occasional lootable corpses are all pre-placed in the maps. Most of your money comes from looting wall safes, hacking personal accounts and direct funding from the Illusive Man.
Final Fantasy VIII opponents don't drop money at all; instead, the heroes get a regular paycheck. However, since your salary will rise or fall depending on how many enemies you've killed since your last check (among other, lesser factors), you'll still want to kill plenty of monsters to keep your funds up. In addition, many monsters drop valuable items, such as bones or teeth, that can either be refined into magic or useful items, or sold for extra gil.
Final Fantasy XII's enemies don't drop money, unless they're the kind of people who you'd expect to be carrying money around, i.e. humanoids. However, they do drop valuable hides, minerals, and so forth, which can be redeemed at shops for actual currency. The looting system is a bit disturbing, as it allows you to steal skin and skulls from enemies while they are still alive and then have the same loot from a drop.
In Final Fantasy XIII, you cannot acquire money from enemies. Instead, you acquire items based on the enemy type, and how strong it is. Some of these items can be sold for quite a lot of money, though. Getting these items is completely random, and most of the valuable resources cannot be acquired until very late in the game, meaning that you'll be going through most of the game with nothing more than a handful of pocket change. The sequel goes back to the standard use of the trope, while simultaneously doing away with most need for money in the first place.
In Eschalon Books One and Two the most a non-humanoid enemy is capable of dropping is either its hide or an edible bit of some kind.
Etrian Odyssey monsters never drop money. Instead, they drop monster giblets, which are sold to the shopkeepers for them to turn into weapons, armor, and items for you to buy.
In Lunar: Dragon Song, you essentially get money for fighting, but not directly. Instead, you get worthless tokens (whiskers, rusty kettles, and whatnot — the game calls them Sundries). Selling them one at a time gets you a pittance; the real money comes from filling a customer's order for a bunch of items. What's more, when you're fighting for items, you don't get experience, and vice versa. This one really makes you earn your income rather than just finding it.
Video Games —Turn-Based Tactics
Totally averted in X-COM. Dead or unconscious aliens have only the weapons and equipment they were carrying (though looting them in combat is occasionally useful, for instance if you've run out of ammo and they happened to be using the same clips). Their ships and bases have no money. Even the gold-derived Zrbite is more useful for fuel and parts. Though of course everything can be sold later for funds, even alien corpses.
Table Top Games
Most modern Pen and Paper RPG avoid the trope: An enemy will generally only drop what they carry, and only enemies who should have money drop money. Exceptions can be made for certain creatures, like dragons whom are often described as hoarding huge treasures.
A fair number of modern tabletop RPGs also handle wealth in a more abstract fashion or handwave it altogether, usually based on some idea like "the name of the game is adventure, not accounting!". Characters in such games simply don't have to track exact change or loot every last corpse because they can already reasonably expect to have decent gear and be able to cover daily expenses (at least up to the limits of their general wealth rating, if the system uses such a thing); things like the acquisition of significant new wealth or other new and improved assets tend to be more plot points and/or part of character advancement here.
On one hand, it makes no sense for the monsters and encounter areas of the gameworld to come pre-stocked with loot. It also makes no sense for feral beasts and the shambling undead to walk around carrying fabulous cash prizes. On the other hand, gold coins are shiny and make a fun jingling sound when you have lots of them.