A Terran Empire warship that hailed Discovery shortly after it arrived in the mirror universe, forcing the crew to pose as their ruthless counterparts for the first time.
The ISS Cooper is a starship of the Terran Empire in the mirror universe. It appears in the Discovery episode Despite Yourself.
Discovery has just reached the mirror universe and its crew are still working out where they are when the Cooper hails them. Records recovered from a wrecked rebel ship show that Discovery's counterpart is commanded by Sylvia Tilly, and that Lorca's double is a fugitive.
Tilly has to answer the hail as Captain Killy, while Lorca stays out of sight and feeds her lines. The bluff works and the Cooper moves on. The encounter persuades the crew to repaint the ship as the ISS Discovery and to send Burnham, Lorca and Tyler to the ISS Shenzhou in disguise.