Question about HL2 EP.2 (ending was sad btw)

what are these things?
ive seen them before and they look like a mix of organic and robotic life.
and do they just kill people or do they eat there brains?
serious questions are serious

they creep me out.
it makes me wonder how they can fly and use the force and shit xD

Thanks for making me remember how shitty the graphics were. YAY source engine! Either way, I think the robotic is mind controlled? They use them as their only appendages. Could be life support/monitor as well.

They seem to be some sort of message carrying device, iirc. They have some sort of telepathic powers.