THE OG GIANT ANT
First off, 'giant' is relative, they're actually about the size of a smallish dog. This ain't Them!
|you'll want the Gamma World bestiary for truck-sized ants and other atomic mutants|
They still have 2hd though, with soldiers having 3hd and poison. Presumably this is due to them being able to lose legs and antennae without dying of bloodloss and shock. Add a really high AC on top and giant ants are actually considerably scarier than orcs and other humanoids, at least stat-wise. While they're pretty stupid, they're not zombie-stupid but they're still not something the average party can communicate with, and they're also fast. Throw food at them and run to the nearest door to spike shut is probably a wise go-to.
A colony of ants that loses its 10hd noncombatant queen (guarded by 5d10 workers and 5 soldiers, mind you) is confused for six rounds, then leaves the nest, presumably with an egg that will become a new queen in tow. Or maybe just to wreak havoc on the countryside while slowly dying off, it really doesn't say. But this provides some incentive for a sort of 'assassination mission' to drive off the ant hordes, though the treasure type leaves much to be desired(a chance of a few gems and potions). Mostly I like their presence as 'dungeon cleaners.' Most monsters don't want to mess with giant ants, and they're small and climby enough to avoid many trap triggers and sneak through gaps in the dungeon, and so any edible scraps(ie, corpses) could be carried off by the ants and save the DM book-keeping by keeping the dungeon clean. Hooray, ants! (As an aside, I'd think the same would be true IRL for having ants carry off crumbs, but most people despise ants in their house. Personally I only have beef with them farming aphids on garden plants.)
SUNSET REALM GIANT ANTS
|what a cutie|
Giant ants are ok as is, but it can't hurt to spice them up a bit. The explanation for them getting huge in the first place would be the semi-common occurrence of ant eggs being exposed to the light of the Spring or Autumn moons, so ants of unusual size would be exclusive to the Moonlands, though occasional attempts at moving into the Daylands would probably be possible in borderlands. Their most common predator would also be overgrown Birds of Spring/Autumn, as well as Brain Wasps, another Autumn-induced mutation of hymenoptera. In any case, their sizes would actually be variable based on the time of moonlight exposure.
1. Honeypot Ants- In a medieval world where sugary treats are rare and expensive, raiding a bunch of fat 'honey' filled giant ants would be lucrative venture, and one slightly less terrifying than doing the same with giant bees.
2. Aphid Farming- If giant ants, why not giant aphids? Again, this provides a sugary treasure to interest adventurers, as well as menacing plant life with giant aphids.
3. Mushroom Farming- And of course I mean Shriekers and other amusing monster-mushrooms primarily, though alchemically useful mushrooms that only grow in well-established ant dens could provide incentive to interact with giant ants in ways outside of 'aw hell naw, run for it Bartleby.' Also could turn into a cordyceps zombie outbreak to change up the dungeon. Also, many mushroom farmer ants cut leaves, so dryads, treants, and other leafy critters could offer rewards for dealing with leaf-cutter ants.
4. Talking Ants- And bam, the ants are now just another faction to play with. Alternately even funnier if they are regular-sized ants and relate to the players as cultists of eldritch abominations relate to their objects of worship. There was a reddit post or something to that effect that was quite amusing, stuff like ants surrounding humans in tiny rune-circles, chanting the human's name, and informing the hooman that they are bound to serve the ant (they aren't) and bring them a whooooole bag of grain, or make them queen, or destroy the red ants, or whatever.
|ia, ia, Susan fhtagn!|
5. Ant People- While there is naturally a considerable difference in the religious details, I really like skerple's ant people, especially adoring 'dig into hell to rescue ancestral ignorant heretics.' I'd probably make mine slightly cuter because I'm a filthy weeb and the hymenoptera order of insects are already halfway to being anime waifus (thin waists, giant eyes, quirky mannerisms) and slightlysimian has cute ant people portraits (among other things) that I wanted an excuse to post
|just look at that clean linework, i'm so jelly|
*(in my setting all animals can talk in languages typically shared by Class or sometimes Phylum, though most rarely bother, on account of actions speaking louder than words. Compared to humans, animals are more at ease with the circle of life and death, having wildly divergent ethical and moral outlooks on common events like butchery and breeding at a farm or being preyed upon in the wild, and so are typically exempt from undeath or worse, becoming an adventurer. Ants, for example, would be far more outraged by a worker impersonating a queen than a human treading on a half-dozen of them.)
The subterranean corpse hoarding behavior of most giant ants would also make them considerably more tolerated by humans in lands where the dread moon Skull waxes ascendant. While most human spirits would prefer to not spend their afterlife dreaming amongst ants, it is certainly preferable to having your corpse hijacked by moonlight and turned into an undead murder-monster, and so having giant ants in a region wracked by war and brigands should provide an extra failsafe to forestall potential undead moonspawn apocalypses, which is nice.