The "Ticks"(if you read nothing else here, read this.)

Everyone in the Pit has a "tick"/"bracelet". The formal name is yet unknown but the devices lay across the arm and look vaguely metallic. They're biomechanical, nanotechnologically constructed to mesh with the body. If you cut one it will bleed your blood, but it's very difficult to damage them and even if they are they seem to have VERY swift regenerative capabilities.

The device bonds with the nervous system of the person it's attached to.
It can act as an amplifier for psychic ability, it can create and dispense chemicals into the body and it can transfer mild ideas and impressions to the "host".
The device also chooses the first and closest person with another tick and "bonds" the two people together (unless hacked by Luke)
Being too far apart causes pain and the release of detrimental chemicals.... this may be subject to change.
The effects vary from person to person but with/close to a partner the Ticks will do various rewarding things like lead the hosts to food through mentally imprinting stash locations, giving extra bursts of strength, focusing the mind for quicker thinking, raising dopamine levels...
Third Gen Ticks seem to allow for domination of other experiments, as well has having the capacity for Bonds of three people.

The Bond is a big deal in the Pit... at first it was thought that the first person you Bonded with you were stuck with. Two men from an earlier experience in the pit found ways around the Bond and were even able to "Hack" the Ticks of others to switch/deactivate/create Bonds. This takes a great deal of practice and cannot be done by just anyone. (what this means OOC is that your character must receive approval and earn the ability to hack, or that you must get approval to "accidentally" hack, which is also a possibility.)