system
Given the following post, respond as if you're commenting on Reddit:
human
[Mass Effect] How do drones like Glyph or Chatika work?

Both the info and combat drone look like holographic  projections, they can change size and are practically see through. Yet they must require some sort of physical structure to house it's VI, mass effect core for firing bullets, and either rockets or some form of flame thrower. However as we can see through them we never see such an object large enough to do so.

How do these drones work?
gpt
They are not projections. Omnitools can be used to fabricate small stuff. For example, the omniblade, commonly used for melee attacks, is made of silicon carbide, and suspended in a mass effect field. They can also be used to make graphite rods for the M-920 Cain particle accelerator, from other heavy weapon ammunition. 

Iirc they transform omnigel into certain materials. With that and eezo, you can make a small, disposable drone.