The “Burrow” ability, researched at the Lair, allows zerg units to dig into the ground, hiding from view and enemy attacks. Once this ability is evolved, most zerg ground units will instantly be able to burrow. Burrowing can provide several advantages for the zerg, both offensively and defensively; its power should not be underestimated.
The following Zerg units can burrow:
- Roaches (Can move while burrowed and will regenerate faster if tunneling claws is researched at a roach warren)
- Infestor (Can move while burrowed, but can only use the infested terran ability while doing so)
- Detection reveals burrowed units and allows them to be targeted and destroyed.
- Burrowed units can still be hit with area-of-effect (AoE) attacks and abilities, even if they can’t be seen.
- Most units cannot move while burrowed.
- Burrowed units cannot move through most barriers that would normally stop them when un-burrowed, such as terrain or units. However, they can pass underneath forcefields.
- Units can still burrow on metal-surfaced maps.
- Burrowing can help preserve damaged units that need time to regenerate their health.
Burrowed units can be used to ambush your opponent to great effect. Banelings can burrow and then detonate underground, allowing you to catch your opponent’s units off-guard and inflict terrible, terrible damage on their light units. Burrowed infestors can sneak around the map and drop infested terrans at expansions, near siege tanks, and at ramps leading into bases. Roaches can pop up at an expansion and assault workers or key buildings, and then burrow to escape.
Burrowing can be a major boon to your scouting. Burrowed zerglings can keep an eye on every resource node on the map (as well as any key choke points) at a minimal cost. Burrow zerglings at optimal build locations (near mineral clusters and vespene geysers) to force your enemy to build further away or move to another expansion area. If you wish to observe enemy expansions, burrow zerglings right behind or near a mineral cluster. Even if your opponent can detect the burrowed zerglings, they may not actually spot them.
Burrowing can also be highly useful for expanding. In the early to mid-game, burrow drones at key expansion areas and keep them in hiding until you are ready to expand. Should your main base be invaded and lost, your burrowed drones will provide you with the chance to quickly rebuild without having to worry about moving them through enemy forces. This tactic can be particularly handy during Team or Allied games, where you can ask your allies to occupy the enemy while you rebuild.