Anchoring Weapon Fusion
(from Starfinder Core Rulebook)
A weapon with the anchoring fusion has a chance to immobilize its targets. The weapon gains immobilization as a critical hit effect. If the weapon already has a critical hit effect, choose each time whether to apply the weapon’s normal critical hit effect or the immobilization effect. A target affected by the immobilization critical hit effect is unable to move from its space under its own power for 1d4 rounds. It cannot use any form of movement, including teleportation effects, to change its position. If the target is entirely contained in a mobile object (such as a starship or large vehicle), the target is immobile relative to its location within that object. Other creatures and forces can move the target normally.