Combat profile
Values below are the current Minecraft 26.3 / NeoForge defaults, before wave scaling and additional equipment. Existing server configurations can differ. Edit this mob's own registry entry in base stats and abilities; changes are not inherited from the ordinary Skeleton entry.
Building and ranged defense
Uses engineer Nexus navigation and mining, builds with Dirt by default, and holds an Engineer Hammer while constructing. Defaults enable bridging, upward block placement, descending spiral staircases and structured engineer towers with ladders. stairing is disabled by default and can be enabled separately. The construction material is configurable through building_block. See terrain learning, tower reuse and repair.
With a visible, living attack target within 16 blocks, it stops moving and switches to a bow. The first shot follows after 20 ticks (1 second); subsequent shots occur every 40 ticks (2 seconds), at 20 TPS. When the target moves beyond 16 blocks, dies or becomes hidden, it returns to its hammer and engineer work. Its engineer melee goal is replaced by this ranged defense.
With Mob Griefing enabled, a grounded Builder on a valid engineer-tower platform checks once a second for room to place a summoning gravestone. The position is left of the platform center when looking from the ladder toward the center. It needs a replaceable, unobstructed space over solid support and never overwrites an existing gravestone.
Builder helmets — five blocked head hits
Both the Skeleton Builder and Wither Skeleton Builder start with a protective model helmet. It blocks five successful targeted head hits from player melee attacks or projectiles. The fifth hit is also blocked, then the helmet disappears. This is separate from ordinary armor and from pumpkin and melon equipment.
Aim determines protection: the attack must intersect the modeled head before the body. Body hits deal damage normally and do not spend helmet protection. Player melee checks respect attack reach and solid block cover. Explosion damage and damage that bypasses invulnerability are not canceled by this helmet.
Each blocked hit produces a shield-block sound and a brief boat-like helmet wobble. Remaining protection survives saving and chunk reloads; reloading does not restore five hits. The helmet does not enlarge the movement hitbox: a normal Builder fits through a two-block-high opening, and a Wither Builder needs three blocks.
Counterplay
Intercept it before it finishes a tower. Cover interrupts its short-range bow defense but also lets it resume construction. Break its gravestone to stop repeated reinforcements, prepare for the extra mob released on removal, and eliminate the Builder so it cannot place another. Shared towers can be repaired; removing only a ladder is not a lasting defense.
Its fireproof ability is off by default. The Wither Skeleton Builder is the fire-immune Nether counterpart with a damaging aura.
For current Minecraft 26.3 / NeoForge block mining and construction clearance, this Builder uses a 1× digging multiplier. The held tool, Efficiency, Haste, Mining Fatigue and water/air conditions determine the actual rate; construction headroom is cleared through the same timed process.
Drops
The dedicated loot table gives 0–2 bones; it does not use the full vanilla Skeleton loot table. No Pigman Engineer pork or leather bonus is added. As an IM living mob it also independently has a 25% chance of 1 Small Remnants. Equipment drops follow the normal equipment rules; its model helmet is not a guaranteed helmet item.
0–2 bones
1 Small Remnants • 25%Spawning and configuration
Selected by active wave themes or created with its dedicated spawn egg. The default spawn location is default: use the invasion's selected layer, normally ground, with the global spawn-layer rule taking precedence. To choose a per-mob layer, see spawn locations. Ordinary vanilla Skeleton replacement does not guarantee this specialist.
Default themes: ARMORED, RANGED, MIXED, RANDOM, RANDOMHELL, UNDEAD, SKELETONS. Use theme editing to change selection. Wave cost is a budget value, not an egg crafting recipe.
With command permission: /give @s invmod:skeleton_builder_spawn_egg. The icon here is the original vanilla family texture referenced by the mod item model; the egg has its own item and entity IDs. See Nexus equipment and team binding for egg spawns.
Related: Skeleton, Skeleton Builder, Wither Skeleton Builder, Skeleton Breacher.