Ensnaring Weapon Fusion
(from Starfinder Armory)
The ensnaring fusion binds the target on a critical hit. On a critical hit with this weapon, you can apply the entangle weapon special property. The entangle effect ends after 1 minute if the target has not already escaped it. If the weapon already has a critical hit effect, when you score a critical hit, you can apply either the weapon’s normal critical hit effect or the entangle effect. If you successfully affect a target with both the entangling and ensnaring fusions on the same attack roll, only the ensnaring fusion applies, and your use of the entangling fusion is not consumed. Only weapons that deal bludgeoning, cold, piercing, or slashing damage can benefit from this fusion.