Flier-Bot

The Flier-Bot or Flier is an enemy encountered in System Shock.

Overview
"This wandering security robot doubles as a portable welding bot capable of working on vertical surfaces. A self-governing mango-orientation device and flight turbines keep the flier-bot stable during routine maintenance work."

- Catalog of Robotic Assistants on Citadel Station

These flying machines can be mostly found on the Security Level, and have 2 methods of attack - an energy beam if you're close enough and gas grenades if you're out of primary range.

Strategy
Energy weapons and Magnum Pistols work well against these enemies.