Fleshmass heart

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Fleshmass heart

Fleshmass heart

Base Stats


The fleshmass heart is a structure, entity, and event added by the Anomaly DLC.


When the "Something From Below" event triggers, a random 2x2 area will begin to shift and crack apart. Two in-game hours later, a fleshmass heart will emerge at this location. This cannot occur until after you've attuned the void monolith.


The fleshmass heart is a large immobile entity which attempts to overwhelm your base with its unnatural growth. Immediately after erupting from the ground, the heart will begin spreading fleshmass around itself, as well as spawning a pack of fleshbeasts for defense. Over time, it will continue to grow and periodically release more fleshbeasts. While these fleshbeast packs may be easy enough to fight off, this is not a threat that can be survived passively; the fleshmass heart will engulf large sections of the map in a matter of days if not violently pruned back. This growth spreads unevenly as the fleshmass sends out tendrils of flesh in random directions, then fattens these tendrils until they merge before repeating the process. Growth occurs in spurts, with the heart resting to gather biomass before aggressively spreading anew. The time between these phases seems random, but you can expect multiple growth spurts each day.

The only way to stop this entity's growth is to destroy the heart itself, but it is immune to all forms of damage, simply regenerating from any attack instantly. This makes it impossible to defeat upon arrival. Instead, you need to wait for it to generate nerve bundle structures within its fleshmass. These green-veined structures drop neural lumps when destroyed, which can be analyzed to reveal the heart's weakness. After analyzing three lumps, any pawn which is able to reach the heart directly can use the "Trigger Tachycardiac Overload" action to destroy it. One nerve bundle is generated upon the fleshmass heart's arrival, and additional clusters generate at random over the next few days.

Complicating matters, the fleshmass will occasionally respond to the destruction of fleshmass tiles by spawning more fleshbeasts. These can emerge from any tile of fleshmass which borders unclaimed territory. If you allow tendrils to spread near your base, these spawned entities can show up dangerously close to your non-combatants. Additionally, the fleshmass heart will generate spitter structures as well, extreme long-range mortars that vomit acid balls at your pawns every three hours. These attacks ignore walls and roofs, so try to destroy them before they have an opportunity to act. Unfortunately, they can appear anywhere within the fleshmass; a spitter that generates well within the entity's interior is very difficult to defeat without mortar fire of your own. Spitter structures are durable and tend to spawn at the same time as nerve bundles.

The spreading fleshmass can be contained in a variety of ways. Most player-made structures prevent new flesh from growing, with the exception of doors which are destroyed instantly. Pawns that are in the way of new growth are pushed aside and can be trapped if not careful. If fully walled in, a fleshmass heart will grow until it fills the entirety of its confines, preventing it from overtaking the map. However, it will continue to produce fleshbeasts and spitters until properly dealt with.

Upon defeat, the heart will burst and the remaining fleshmass on the map will gradually die off. However, any remaining fleshbeasts will be unaffected. The heart will drop several stacks of twisted meat and a fleshmass nucleus, which can be captured and suppressed to steadily produce more twisted meat. However, if not suppressed, the nucleus will eventually regenerate into a new fleshmass heart. Alternatively, you can destroy the nucleus for shards.

Fleshmass Growth Cycles occur every 12 to 36 hours with an average time of 20 hours. The amount of flesh grown and enemies spawned in a growth cycle depends on raid points and the status of the Fleshmass Heart. If there are less than 3 Nerve Bundles then another Nerve Bundle is grown in a growth cycle. A maximum of one Nerve Bundle and one Spitter can spawn each growth cycle.

Fleshmass Spitters can fire every 2 to 3 hours at any unroofed target between 7 and 42 tiles away.

Mini-cycles can occur on average every 2 hours between standard Heart growth cycles. These mini cycles can spawn fleshbeasts and fleshmass walls.


Combat tips[edit]

Since the spreading fleshmass can´t grow through walls, to limit its spread it is crucial to contain the fleshmass in an early stage. Wooden walls can be a good choice for containment, since they can be built much faster than stone walls. Also you can use wood chopped right next to the combat zone to speed up the process. Psycasters with the Wallraise ability can help you create a fast but temporary containment zone. Graves are considered walls by the fleshmass as well, and can be dug quickly for not cost.

Try to destroy as little of the fleshmass as possible to reduce the chance of triggering the fleshbeast spawn. There is no need to try to clense every piece of flesh before the heart is defeated!

Also there is no need to batte the heart if there are no nerve bundles or spitters left. So withdraw your combatants and let them rest while you wait for the next spawn.

Fleshbeasts and spitters that get submerged by the fleshmass will get relocated to a free area nearby. Those areas can also be on the other side of your containment walls. Those enemies should be cleared as they can attack not only your pawns but also the containment walls from the other side and might free the fleshmass again. Make sure to rescue fallen combatants as well as their valuables as those can get pushed of the map by the growing fleshmass if the loot is too close to the maps borders.

When a new nerve has spawned, open one of the walls and try to make your way with as less damage as possible to the fleshmass. Also be cautios of enemies trapped inside the flesh as they might get pushed right next to your combatants when the fleshwall fully submerged them.


After being defeated, the fleshmass heart can be relocated to a more accessible and prepared location, allowing the player to farm it for resources.

The heart itself should surrounded by passable buildings that block fleshmass growth - graves are the ideal choice as they are effectively indestructible outside of direct player action. This places a hard limit on the flesh mass expansion for maximum safety. If the ground does not support graves, barricades are a good substitute. This containment area should be fully walled in except for a single entrance, multi-layered walls are preferable.

Having an active fleshmass heart can cause some problems if friendlies from another faction arrive, as they will actively target live fleshbeasts, unless the containment area is completely walled in, and the line of sight blocking will also help prevent spawned fleshbeasts from causing interruptions at inopportune times.

The area that is allowed to be covered in fleshmass should be about 3 tiles wide, so that spitters and nerve bundles can be destroyed without having to go through layers of fleshmass, but long enough for the player to be able to destroy fleshmass in sufficient amounts to trigger fleshbeast spawns.

A contained fleshmass heart can produce fleshbeasts indefinitely and in a controlled manner. This grants the player some potential benefits:

  • Wounded fleshbeasts can be captured for anomaly researsh, electricity and bioferrite harvesting
  • Dead fleshbeasts serve as an infinite source of twisted meat for feeding ghouls and carnivorous animals directly. Twisted meat can also be used to produce kibble and nutrient paste to feed a larger variety of other animals, or to feed prisoners if you intend to cause crisis of belief mental breaks
  • Twisted meat can be used to produce chemfuel
  • Fleshbeasts can serve as an average-threat target practice to train combat skills of your colonists and ghouls
  • Twisted meat is used in some anomaly-related crafting recipes like serums
  • Dead fleshbeasts can be fed to harbinger trees to grow them

Version history[edit]