Universal Rule.
The model cannot declare any Charges, and other units cannot declare any Charges against the model. The model and other units ignore each other regarding the Unit Spacing rule for all movement and can touch and move through one another during any movement (note that this includes Ambush and that this means that the model can be placed in base contact with other units when Summoned). The model never blocks Line of Sight (remember that this also affects Cover as it can never contribute to Hard Cover).
When the model touches another unit, the model is immediately removed as a casualty, and the other unit immediately suffers 3D6 hits with Strength 2 and Armour Penetration 1. If several units are touched simultaneously, the Active Player chooses which unit suffers the hits. If the model was removed due to another unit moving into contact with it, that unit suffers an additional 2D6 hits.