“So I was thinking about goblins in my game, and came up with an idea I thought was kind of fun. Figured I'd post it for anyone who wants to swipe it.
In my game, I want goblins to be scary, even though they're mechanically identical to the usual low-level baddies. Mostly I'm swiping the Pathfinder mode of Gremlins-inspired craziness for my goblins, but rather than being cowardly, I'm planning to make them gleefully suicidal, with absolutely no concept of self-preservation or survival instinct. These guys will throw themselves at the heroes in giggling hordes no matter how many get slaughtered.
Then I got to thinking about why they would have this trait, and an idea struck me: Nematodes. Specifically, nematode cannibalism.
Nematodes are a type of flatworm with an odd characteristic - if one nematode eats another one, it seems to take on the memories of the consumed worm. Yes, really!
Goblins, it turns out, are the same. Goblins don't fear death because they have a very peculiar form of immortality: As long as a dead goblin is eaten by another goblin, all its memories will be passed on to that goblin - including any memories from previous consumed goblins! And since goblins are voracious cannibals, most goblins remember dozens or even hundreds of lives (and deaths), and see it as little more than an inconvenience.
A goblin who eats a hobgoblin not only gains the memories of that hobgoblin, but will begin to grow; over the course of about a month, it will become a new hobgoblin, with the personality and memories of the deceased hobgoblin. This is why hobgoblins are always sure to keep some goblins around, despite their contempt for their inferior cousins - when a hobgoblin dies, assuming it's a hobgoblin the others still want around, they'll go grab the nearest goblin and feed the corpse to it.
However, one hobgoblin eating another is a severe taboo, because of the result - a bugbear, a monstrously huge goblin that hunts and eats other goblins and hobgoblins. (Bugbears tend to be solitary and avoid each other, so what happens if one bugbear eats another is left to the imagination of the GM.)"