An experimental quantum tunnelling device stolen from Daystrom Station and used by Vadic's ship, the Shrike, to open paired portals through which objects, or whole ships, can be moved.
The portal weapon generates two linked openings in space; anything entering one emerges from the other. It was among the dangerous technologies locked away by Section 31 at Daystrom Station.
It is first used in the Star Trek: Picard episode The Next Generation, when a Starfleet recruitment building on M'talas Prime is dropped through a portal from a great height, an attack witnessed by Raffi Musiker. In Seventeen Seconds the Shrike turns it on the USS Titan inside a nebula, sending the ship's own fire back at it and blocking its escape.
Worf and Raffi's inquiry later shows that the theft of the weapon was partly a cover for the removal of something else from the station.