Mechanical

From StarCraft Wiki

Mechanical units are composed of mechanical components and possibly a biological component. Most mechanical units are vehicles with a terran driver. The protoss dragoon is another example, and is cybernetic in nature. The SCV is counted as both mechanical and biological.

Due to their biological components, mechanical units are vulnerable to some special abilities, such as a queen's Spawn Broodling attacks. However, they are immune to some special abilities which can affect organic units, such as the science vessel's Irradiate ability.

Due to their mechanical component, they are vulnerable to abilities like a ghost's Lockdown ability.