Opportunistic Weapon Fusion
(from Starfinder Armory)
The opportunistic fusion guides your accuracy when making attacks of opportunity and leaves your foes vulnerable to your attack. You gain a +2 bonus to attacks of opportunity made with this weapon. If your attack of opportunity hits, you gain a +2 bonus to the damage roll for that attack of opportunity. This damage increases by 1 if the weapon is item level 5, and by an additional 1 for every 5 item levels thereafter. Only melee weapons can benefit from this fusion.