Gift of the Machine Gods. As a creature of ancient arcana (technology), the robot gains many damage and condition resistances and immunities, but they are also susceptible to electrical attacks:

• Automatically gains a proficiency or feat as needed though it can only have one new ability active at any given time. It does this as part of short rest downloading the knowledge it needs to finish a mission at hand.
• Has advantage on Wisdom (Perception) checks that rely on sight or sound and has double proficiency bonus in the Perception skill as it constantly scans its surroundings for danger.
• Is combat-hardened and has a damage threshold equal to half its CR rounded down; that is, it reduces all individual attacks by the threshold numbers damage.
• All robots have a weakness to lightning-based damage. They have disadvantage on saving throws against attacks that do lightning damage and, on a natural 1 are stunned until the end of its next turn. Lightning damage also bypasses all damage reduction.

Camouflage. The robot’s outer shell contains color-shifting polymers that allow the creature to blend into any background. Though not truly invisible, they are hard to pinpoint. The observer robot has advantage on Stealth checks.   Transmit Senses. The robot is outfitted with several sensors, cameras, and microphones that allow it to record events and transmit them to another location. The robot can broadcast everything it can see or hear to a receiving device if it is within 10 miles. The robot can also transmit its senses to another spectator robot forming a chain back to a commutation device.   Colony. The robot swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Tiny construct. The swarm can’t regain hit points or gain temporary hit points. A swarm takes half damage from attacks that use an attack rolls and double damage from effects that require it to make a saving roll. Creatures that are not Swarms are distracted while they remain in the swarm’s space or within 5 feet of it and have disadvantage on attack rolls, and Constitution saving throws to maintain concentration. The area of the swarm is considered difficult terrain.