Saurus Scar-Veteran on Cold One

If the unmodified hit roll for an attack made with a Celestite weapon by this model is 6, that attack scores 2 hits on the target instead of 1. Make a wound and save roll for each hit.

You can use this command ability in the combat phase. If you do so, pick 1 friendly SAURUS unit wholly within 18" of a friendly model with this command ability. Until the end of that phase, if the unmodified hit roll for an attack made with a melee weapon by that friendly SAURUS unit is 6, that attack scores 2 hits on the target instead of 1. Make a wound and save roll for each hit. A unit cannot benefit from this command ability more than once per phase.