Infernoboys and Medified.
They are mainly found in Fastlane, as the name implies.
They have been located in maps like Harvest meaning they migrate to other places.
They mainly consist of an smiling disformed engineer, with thin legs, a shortened torso, and a hardhat in their neck.
Abilities and Weaknesses
Their abilities have not been shown, but we can assume they are dangerous as every person who sees them instantly becomes suicidal or cowards in fear.
They can be defeated, as a robot engineer managed to kill them with a turret.