Combat profile
For Minecraft 26.3 / NeoForge, wave base values and supported behavior can be changed per registry entry: see health, damage and base armor and mob abilities. Tier, size and wave scaling still apply.
Behavior
The server's enable-silverfish option controls IM Silverfish spawning and infestation. Disabling it does not remove existing mobs.
It retains quick vanilla melee movement but adds invasion-specific infection and block-transformation goals. Without a nearby player it seeks and damages the Nexus.
Permanent infection
A successful infection adds the persistent entity tag invmod.infected to the host, and the infecting IM Silverfish disappears. This marker does not expire with a status-effect timer; it is separate from the temporary vanilla Infested effect.
When the host later dies, it releases 1–4 IM Silverfish. Hosts of the vanilla Enderman class instead release 1–4 IM Endermites. Parasites inherit the host's Nexus binding when it has one; otherwise they use an active Nexus in the same dimension, if available.
enable-silverfish=false prevents new Silverfish infections and the Silverfish release from marked hosts. It does not prevent the Enderman-class host's Endermite release. Disabling Silverfish does not remove every consequence of an existing infection.A Versus owner can also buy Infestation: an independent 0–100% chance for eligible new army/egg hosts, at 10 Flux for the first level and 5 more for each later level. It applies the same permanent marker and death-release rules.
One-use stone bridge
During a successful bridge path action, an IM Silverfish places a stone block in air or fluid and then dies. The action has 45 build ticks configured (about 2.25 seconds at 20 TPS). A failed placement does not trigger this sacrifice.
This can create a foothold across gaps or liquid in your defenses. Unlike an Engineer, it cannot survive a successful placement to continue building. Defeat it before its bridge completes.
Drops
Loot delegates to the vanilla Silverfish table, which normally contains no item drops.
Vanilla replacement
During an active Nexus invasion, eligible vanilla Silverfish can be replaced by this IM equivalent with 30% of their current health.