A game: cite of an example where the universe has evolved a natural system exhibiting coordination of behavior by a full decentralization of group consensus, and I will tell you why it is wrong.
The starfish.
https://en.wikipedia.org/wiki/StarfishWhile a starfish lacks a centralized brain, it has a complex nervous system with a nerve ring around the mouth and a radial nerve running along the ambulacral region of each arm parallel to the radial canal. The peripheral nerve system consists of two nerve nets: a sensory system in the epidermis and a motor system in the lining of the coelomic cavity. Neurons passing through the dermis connect the two.[28] The ring nerves and radial nerves have sensory and motor components and coordinate the starfish's balance and directional systems.[5] The sensory component receives input from the sensory organs while the motor nerves control the tube feet and musculature. The starfish does not have the capacity to plan its actions. If one arm detects an attractive odour, it becomes dominant and temporarily over-rides the other arms to initiate movement towards the prey. The mechanism for this is not fully understood.
Good choice. There are a couple like this, and some better ones, but they are still wrong.
For the starfish has no central nervous system, but it does have a radially centralized body plan - and more subtly, a solid body is an information signalling medium of its own. If one arm pulls, the rest of the creature comes with it. A brain need not agree to this, or even a network of nerves. The entire physical unity of its mass does the job of "maintaining consensus" about a direction for the creature to move. To lose this consensus (such as arms pulling in opposite directions, or being pulled by outside forces) would be to physically fragment the creature. The nervous system described above is an overlay network which helps prevent this from happening.
Also, there are natural constraints to how big starfish can become before they cannot sustain physical integrity.