Stun

Effects:
Stunned creatures are unable to act or move. Certain creatures with channeled attacks, such as Praetorian acid spit, will be interrupted by stuns. Dwarves are normally immune to stun outside of some Creature attacks. In these cases, "Stunned" dwarves can still move and act but their speed is reduced by 50% for 1.5s.

Sources:
There are many sources of Stun available to Dwarves, they are listed below in order of % chance, then Duration.

Stun Resistance:
Some creatures have a "resistance" to stun. This means while they can still be stunned with the same % chance, the stun duration will be reduced. This stun resistance applies to all variants within a category unless specified.

Stun Cooldown:
Some creatures have a cooldown (StaggerImmunityWindow in the gamefiles). This is a delay between possible stun triggers, which prevents them being stun-locked until death.

Immunity:
Some creatures cannot be stunned, a large portion of neutral and stationary enemies cannot be stunned. Below is a list of Mobile Hostile Creatures Immune to Stun. If a base type of creature is immune, then all variants are also immune (i.e. Bulk Detonator & Crassus Detonator):
 * Ebonite Variants (all)
 * Flying Rocks
 * Glyphid Bulk Detonator
 * Glyphid Crassus Detonator
 * Glyphid Dreadnought
 * Glyphid Oppressor
 * Mactera Grabber
 * Naedocyte Breeder
 * Nayaka Trawler
 * Q'ronar Youngling
 * Q'ronar Shellback
 * Xynarch Charge-Sucker