The Dragon's Teeth is a level 2 structure available to both the CORE and the ARM. It is not controllable and has no purpose other than providing blockade; it can be built at choke points to block the enemy's advance or around towers to prevent units with low firing trajectory from damaging them. It is not counted into the unit limit and can take quite a beating before it breaks, however construction units can make quick work of it by reclaiming.
This barrier is designed to slow down enemy ground vehicles. It is very strong and it takes a lot of hits to destroy one.
These slow the movement of ground units.