I’m a big proponent of rolling twice on an encounter table and combining the results. 1d6 goblins plus a wandering knight becomes stumbling across a knight fending off goblins mid-battle, or a lost knight who has convinced the gobbos she is their god and keeps giving you “play along” looks, or whatever.
However! I’m also a big proponent of not making extra work at the table. Work isn’t bad, and games probably aren’t games if there isn’t at least a *little* work somewhere, but at the end of the day we’re here to play. And making stuff up on the spot is work, even if it can be fun, and gets in the way of play.
So instead of getting the GM to come up with what these combos mean at the table, how about writing your encounter tables as a list of combos in the first place? This has the added benefit of starting a lot of your writing for you - coming up with 3 encounters, then combining them in every possible way (1+1, 1+2, 1+3, 2+2, 2+3 and 3+3) basically doubles your initial ideas. You can also show some of the location’s faction interactions of ecology in a more direct and useful way.
This example table is loosely based on the first “stratum” of the megadungeon in Etrian Odyssey V (which I recently dredged up my old 3DS to play again once I saw how much they’re charging for the new Switch remasters). That game has some fun inter-monster interactions in encounters, but with our medium we can of course go further!
1. Acorn-men + Acorn-men. These cheeky little bastards are born when wildfire spirits settle in hollow nuts and fruit pits. Love making noise and mischief. Water douses their spark. When multiple groups gather, they have loud and raucous parties that can start forest fires if left unchecked.
2. Acorn-men + Wild hog. Hogs love eating fallen nuts from the forest floor, and do not seem to care if the nuts come alive and protest. Consuming the wildfire spirits within gives them temporary flame breath.
3. Acorn-men + Flinging vine. The long, green tendrils that hang from boughs here are in fact not vines but a type of parasite. They are blind but react to touch, coiling their sticky bodies around their victims and bashing them against tree trunks or throwing them as far as they can. This causes the acorn-men to explode.
4. Wild hog + Wild hog. A breeding pair, the larger stronger female holding back unless threatened, the smaller, aggressive male picking fights with anything that enters their territory. As they need to bulk up to feed and defend the coming offspring, they are easily distracted by food and will go for the simplest target.
5. Wild hog + flinging vine. Smaller hogs are easily flung aside and know to stay away. The largest seem to enjoy the tug of war and sometimes even pull the parasites down from their perches. The disconnected vine then flails wildly like a whip, sticking fast to the hog until it dies.
6. Flinging vine + Flinging vine. When two or more vines get tangled, they unintentionally create a deadly trap. Touching the knotted vines causes them all to pull and attempt flinging at once, which can bring down the trees they are attached to and crush their would-be prey.