Zerg structures are effectively giant organs, making a Zerg colony a living creature. To provide the required nourishment and infrastructure, the Zerg produce a living carpet of bio-matter that invading forces have dubbed the Creep.
Creep is a purple slime upon which all Zerg structures, except for the Hatchery, Extractor, and Nydus Worm, must be built. If the Creep is lost, the buildings take 4.2 damage each second, reduced by Zerg Regeneration to 3.82 dps. Protoss and Terran structures cannot be built (nor land) on Creep. Most Zerg ground units move faster on Creep. Creep spread, across the map and between Zerg bases, is essential for Zerg scouting and defence.
Most Zerg ground units receive a 30% movement speed bonus on creep. Drones, Broodlings, Changelings (not disguised as Zerglings), and burrowed units receive no bonus. Queens receive a 167% bonus, Locusts a 40% bonus, and Spore & Spine Crawlers a 150% bonus. The speed bonus makes it beneficial for Zerg to cover the map in creep, increasing mobility both to reinforce besieged bases and to retreat from indefensible positions. The speed bonus applies to enemy Zerg as well, so in ZvZ it is common to restrict creep production only to areas around and between bases to avoid facilitating enemy rushes.
Creep is a terrain feature, not a structure or unit. Players do not "own" the creep. Thus, creep does not grant vision. Creep Tumors have a sight range of 11, outranging the creep they grow. Hatcheries, Lairs, and Hives grow out to 12.5, but have a sight range of 10,11,12, respectively. Near a Lair, enemies can barely step over the edge of the Lair's creep and remain unseen. The Hive's vision exceeds its creep range, so a unit could be spotted even off creep.
Protoss and Terran buildings (except Auto-Turrets and Stasis Wards) cannot be built nor land on Creep. Zerg may cover the expected site of a Protoss or Terran expansion with Creep, forcing the opponent to destroy the source of the Creep then wait for it to recede before he can take the expansion.
Much of the strategic use against Protoss is the same as against Terran.
Creep spread is very important against Terran because of the prevalence of melee units (Zerglings, Banelings, and Ultralisks) in the matchup. Creep allows the Zerg army to engage much more effectively against the ranged Terran units. Creep spread also grants vision of potential drops.
Creep spread from Overlords may be used to prevent Command Centers from landing at third and fourth base locations, and occasionally even Proxy Hatcheries at the Terran's natural to delay the Terran's expansion. In the mid to late-game, generous use of Creep Tumors severely slows down Terran pushes. The Terran has to stop and scan to destroy them, or risk being forced into unfavourable engagements.
Creep Spread is least important in the mirror matchup since the movement speed boost is gained by both sides. Although spread across the map is not essential, it is still important to spread creep to the third base to allow for defensive movement, especially by Queens.
Creep spread from a line of Overlords creating a creep 'highway' is occasionally used to send Roaches across the map more quickly for timing attacks. Such a move is risky, however, as it is easily countered by Mutalisks.
There are four sources of creep:
- Hatcheries (and Lairs and Hives, which have the same creep stats), which start with a squared circle of creep around and under them.
- Creep Tumors, which are spawned initially by Queens.
- Nydus Worms, spawned by the Nydus Network.
- Overlords, which have the Generate Creep ability.
All of them start with a small area of creep which grows into a large squared circle centred on the creep source.
|Source||Radius||Cycle Time (s)||Starting Area||Full Area (tiles)|
|Creep Tumor||10.5||0.45||9 (3x3)||333|
|Nydus Worm||10.5||0.45||9 (3x3)||333|
- A Hatchery built off-creep will spawn a 3x3 area of creep underneath it whilst it is building. Cancelling the Hatchery allows the Zerg to make use of it, to build proxy buildings or secret tech. As the creep will quickly expire, any buildings there will start to die. You can however place a Creep Tumor on the creep to maintain and expand it.
- Overlords in StarCraft II have the ability to Generate Creep after building a Lair. This ability costs nothing; it is not an upgrade, just a toggled ability. When the Overlord moves, it will stop emitting creep, but resume when it comes to a stop again, without needing to reactivate the ability. The Creep left behind will then decay if it had nothing else to maintain it.
- The Queen's "Creep Tumor" ability costs 25 energy and spawns a Creep Tumor. This Creep Tumor excretes creep and has a single charge to make another Creep Tumor. They are burrowed once they finish constructing, so detection is needed for an opponent to target them. Once a Creep Tumor has been destroyed, the Creep will slowly recede.
- Once a Nydus Worm finishes, it will also generate an area of Creep around it, identical to that spawned by Creep Tumors
When a creep source finishes building, it immediately spawns a few tiles of creep, which spreads to fill an assigned footprint in the shape of a squared circle. Creep spreads two tiles per Creep Cycle. If all creep sources in an area are destroyed, the creep will decay, a few tiles at a time. Creep must spread from adjacent creep, so it will not spread up or down a cliff (except passable ramps) or through a wall. It can however maintain creep not connected to it. For example, if a Creep Tumor is at the base of a cliff while an Overlord drops creep on the high ground, the Creep Tumor will sustain and grow that creep, even if the Overlord leaves.
A Creep Tumor takes about 73 s to fill its entire area, but maps only rarely have such wide spaces, so Creep Tumors will usually fill up their area in less time. If a Creep Tumor is placed right at the edge of another's field, about 42% (138-148 tiles) of its area is already covered and it will take about 42 s to fill its remaining area. Overlords take about 15 s to fill their area.
Faster Creep Growth
Each Creep Tumor is an independent creep source, so two or more creep tumors in the same area will grow creep much faster. Two adjacent creep tumors will only take about 41 seconds to fill (more than half because each one has a sliver of terrain not covered by the other), and three tumors will take about 26 seconds to fill. However, when creep is spread edge-to-edge, two Creep Tumours should take about 17 s to finish, and three about 11 s. The cooldown on the Spawn Creep Tumor ability is 11 s, so three Creep Tumors approaches the limit of efficiency.
The other main way to optimize creep growth is spreading along multiple paths. Generally it is beneficial to have creep covering as much of the map as possible, although doing this obviously increases the amount of micro required to maintain the creep spread rate. Also note that since creep will not spread through impassable barriers (walls & cliffs), a Creep Tumor placed against a cliff has less area to fill, and so fills faster. Thus the Zerg can minimize time spent filling tiles not in the desired direction.
Prior to Legacy of the Void, the creep cycle for Tumors and Hatcheries was 0.6 s and for Overlords it was 0.71 s. In Legacy it was shortened to 0.3 s. In Patch 4.7.1 it was set to 0.45 s for Tumors and Overlords.
Until Patch 3.8.0, Hydralisks had a 50% speed bonus on creep.