A lasso is a weapon described on UA 77.

A hit snags the target (along with the other effects listed on UA 77). When snagged, the wielder of the lasso can take a G action to drag the target moves them 1“ closer to the wielder.¹⁾

To get un-snagged, see the procedure on the harpoon page. Additionally, instead of cutting the line, the victim can take an E action to attempt to snap the line with BB/LG. Only one such attempt can be made per lassoing incident.

See UA 77 for additional rules and stipulations. Also see the harpoon and net.