Infected Behemoth

This is infected version of Mutant. It has a much larger health pool of 1500-8000 hp, but otherwise has the same properties as a normal mutant. It has a very high alertness, even higher than a Harpy. This means it is very easy to pull it from long distances, which can spell doom to your colony unless you are sufficiently prepared. It also generates a lot of noise, attracting more zombies.

Behemoths have watch range of 12, so they can hear Noise within 48 tiles, or 72 in Desolated Wasteland . This means that it's impractical or even impossible to avoid building outside of their hearing range, so player should try to stay quiet until getting enough firepower to kill the Behemoth and everything that approaches colony after it. Use only Rangers for expansion, Rangers and Ballistas for defense, don't build Inn, generally don't build anything within 30 tiles from Behemoth. A good tactic against early Swarms is kiting them through Traps, because unlike other fortifications, they don't make any noise.

20+ Snipers or 35+ Soldiers can kill a single behemoth without attrition.

To avoid splash damage, select group of units attacked by Behemoth, deselect one healthy unit, and order everybody else to move back by two tiles.

Behemoths make much noise with their attacks, which will attract more attackers, rouse nearby Villages of Doom and pull other Behemoths in hearing range. The colony should be prepared to kill not only the Behemoth, but extra attackers as well. Build 2-3 layers of wall in direction of Behemoth, and at least 2 Ballistas; if there are villages nearby, add more ballistas or a Shocking Tower. Having 5 snipers should usually be enough against Behemoth itself and any special infected that arrive after it.

Try to pull the Behemoth as soon as the colony is prepared for it. This will prevent them from ambushing the colony during swarm attack, will allow units to do something else, and will clear big part of map from runners. To do that, make a gate or hole in the wall, order units to target stronger enemies first, and start clearing map in direction of Behemoth, while keeping an eye on its icon on minimap. As soon as icon starts moving, order units to fall back behind walls. Kill Behemoth, kill runners, add more defenses if there is an unexpected stream of infected from undiscovered village.

If there is a village within 24 tiles of mutant's death, it will send new attackers into colony every hour for days, possibly until it runs dry. If there isn't one, the area should be free from runners. Use Rangers to expand into it and send heavier units elsewhere.

If Behemoth runs into unprepared colony and there is a Ranger nearby, she can save the colony by running towards the Behemoth, attracting its attention and running to the edge of the map. While Behemoth is faster, it also has bigger collision box, so other infected will slow it down.