A shotski, or shot-ski, is a ski with shot glasses glued to it. Revelers, by lining up alongside it and tipping it back together, can take a shot a the exact same moment. They can also chant in unison, "Shot-sk! Shot-ski! Shot-ski!" before, during, and after the liquor is shot.
The Shotski refers to a specific shotski made c. 2011. Subsequently that shotski, as well as shotskis in general, grew beloved by both COOP and the Ski Team. Those two groups, which have a fair degree of cross-over, to this day dispute the device's origin.