The Vanduul Harvester is a ground vehicle that recycles all forms of matter and convert it into a unknown 'biological' resource which is the foundation for their technology. It is also used for strip mining. They are usually deployed by a Vanduul Harvester Carrier.
A new variant of the Vanduul Harvester was encountered on Tiber. This variant seem to function as the the source of newer harvesters that are commonly dropped onto Human colonies during raids. These harvesters, visually no different from harvesters observed elsewhere, are, in effect, performing as mobile factories that spread terror throughout the galaxy. Everything from starship wrecks to the bones of fallen soldiers ultimately feed the very enemy they were attempting to defeat.
"I call it paste but it's basically this is like all the resources that they scraped and refined from the planets they conquered. They use those ships called Harvesters, they just set them down and they just basically take everything and refine it and they create - I don't think it's silicon. I don't know if we actually really know what it is, but it's very very strong and and it has this kind of biological look to it and they basically put whatever the weapon they wanted - they put it together and then they stick everything with almost like an outer framing so it don't doesn't fall apart."
Michal Kozlowski, Around the Verse: Vanduul Blade & Shops 'n Trade 
- Virgil I - Starmap. Starmap
- Galactic Guide: Tiber. Transmission - Comm-Link
- Relay Transcript - Around the Verse: Vanduul Blade & Shops 'n Trade. Accessed 2018-06-10.