Starting off, I thought I'd do a dungeon encounter instead of wilderness. Rolling a d8 for level, I got a 1. So we're talking a low level here (possible snooze alert!)
Next up I rolled a 9 for the monster type, giving us (drumroll) Killer Bees! OK, that sounds fun!
Not quite THAT big!
Since this is a wandering/random encounter, the number appearing is 1-6. I rolled a 2. (Just TWO??)
For hit points, the buzzers got a "hardy" 3 each.
KBs are supposed to be pretty hostile, but since they aren't at their hive and the random encounter distance came up at 70', I went ahead and gave them a reaction check and got "uncertain, confused." (8 on 2d6)
So, what we have here are a couple of big ol' bumblebees buzzing around a dungeon corridor not too far from the surface. How do we make that interesting?
It says that the bees live in a hive of 5-30 (5d6), I went ahead and rolled those numbers (20, including these two and the queen, who has 11 hit points). Let's assume the two bees are not terribly far from their hive. Maybe there is an entrance in the dungeon, maybe it's just above the crawl on the surface. The bees aren't initially hostile to the party, but it won't take much to set them off. If the PCs keep their distance, they might avoid a combat. The bees aren't overly tough (AC 7), but neither are low level PCs. KBs are fast and their sting is save or die (though it kills the bee, too).
What are the bees doing underground? That's the question. Perhaps there is some scent they are attracted to. Maybe something disturbed their hive. A clever party might follow them back to the hive and try to steal the honey, which has magical healing properties. Twenty killer bees are a bit much for a low level party to take on in a straight fight, but some clever use of smoke or Sleep might do the trick.
Probably not enough to base a whole adventure around, but an interesting bit of dungeon dressing. Plus, if the party doesn't follow the bees to the hive, you can also tell the players after they die further on that you "gave" them access to magical healing (the honey), but they ignored it. ^__^