I remember some years ago coming across a creature in 3.5e that works in groups and as each individual of the group is slain the surviving creatures increase in strength. Can anyone give me the name/sourcebook if you know what I'm referring to?
I believe this was an official sourcebook, one of the monster manuals perhaps but I'm wondering if it wasn't part of a setting or in something that expands on classes (e.g. Psionics etc) sorry I don't have anything more specific, this is the reason I'm having trouble finding it again.