Bugs In The System
One of a number of vec hider clades characterized by extremely small (insect size) bodies that live in the interstices of civilization.
They employ nanotech to replicate using local raw materials and pride themselves on living unnoticed in the midst of the far larger beings around them. They employ a combination of small size, camoflage and expert data hacking to remain unnoticed. It is not uncommon for Bugs to travel by stowing away on the vehicles or even clothing of others. Bug colonies have even been discovered living on the outer hulls of space habitats and interstellar vehicles, living in the midst of busy habitat clusters or traveling from system to system, sometimes for centuries before they are discovered.
They are a thriving civilization, almost completely indifferent to the concerns and actions of the greater culture in whose conduits, plumbing and dark corners they make their homes. Legend has it that they derive their name from the very earliest days of the Information Age.
The Silicon Generation appears to have started similar to the Bugs, getting their ancestors stored away as "colonization equipment" to be sent to Cog.
The Bugs are of course not invincible or invisible, and certainly the higher order AIs are aware of them. Most of the time the higher S-level hyperturings view hiders like these as at worst harmless nuisances, and quite often as an entertaining extra factor to use in their plans or visions.