Skimmer
(Rule)Description: Models with the Skimmer special rule can move over all other models and areas of terrain, suffering no movement penalties for doing so, such as due to Difficult terrain or moving over an Obstacle. Models with the Skimmer special rule cannot end their movement overlapping other models, nor can they end their movement within an enemy model's Engagement Zone unless they are Engaged with it. They can move over Impassable terrain but cannot end their movement overlapping it - any model that ends its movement overlapping an area of Impassable terrain is destroyed.
During the First Fire stage of the Combat phase, a Detachment with the Skimmer special rule that is issued with a First Fire Order may make a "Pop-up attack". To make a Pop-up attack, the controlling player declares that the Detachment is doing so when it is activated. The Detachment then fires as normal. However, when making a Pop-up attack, Skimmer models trace their line of sight from a position 10" directly above the current position of the model; to determine line of sight, hold the model up in the air and take a model's eye view.
When a Skimmer Detachment makes a Pop-up attack, they remain at their elevated position until the end of the First Fire stage, meaning enemy models can draw line of sight to the Skimmer models as if they were 10" above their starting positions on the battlefield. At the end of the First Fire stage, the Skimmer models descend and line of sight must be drawn to and from them as normal.