Scp

SCP-966-1 and SCP-966-2 are invisible SCPs that can slip around undetected unless attacking (where they become more visible) or injured (with a very noticeable health bar) They do minor damage and are stored under lock and key in Sector 3. However, due to only requiring a L-3 keycard, they are often a target of opportunistic Chaos Militia and sometimes Class-Ds.

A note when breaching: try to get as far as possible without injuring either 966 instance. The health bars are very obvious, but a fully healthy 966 is very sneaky and liable to be overlooked by most.