In the study group's third year at Greendale, Troy and Abed move in together and throw a housewarming party at their new apartment. When Pierce arrives at the party he brings not only a special gift for Troy but also a bottle of spirits for the occasion, Serbian Rum. He brags to Jeff that the imported drink is banned in it's homeland. The pizza delivery guy arrives while they are about to start a game of Yahtzee and Jeff proposes that the roll of a die will determine who will go downstairs to get the pizza. As Abed predicts, he inadvertently creates six different timelines and the Serbian rum becomes one of many various items which factors into how the diverging scenarios play out. It's first only appearance was in the Season Three episode "Remedial Chaos Theory".
In the "Prime timeline", Jeff takes a drink of the rum after learning that Troy and Abed intend on having the study group play Yahtzee. In the six divergent timelines, the bottle of rum is set on the coffee table and doesn't make an impact on any scenario until Troy's scenario plays itself out. In this timeline, Annie slips on a boulder from Abed's Indiana Jones diorama and falls onto the coffee table the rum is on top of. The rum is sent flying and crashes in front of the diorama and the impact shatters the bottle spilling rum all over the floor. Pierce gets shot by Annie's gun when an errant kick after he stands up to assist
her sends his house warming gift, the Norwegian troll doll, into the purse causing the gun inside to go off. Britta exists the bathroom where she was smoking a joint after hearing the commotion. Shocked at the situation, she accidentally drops her lighted up joint onto the floor where the rum has spilled igniting it and causing a fire to break out. Jeff tries to put the fire out with a blanket but the fire spreads up his arm and across the floor to where the now uncovered Norwegian troll doll is . The aftermath of timeline shows that Jeff lost his arm and this, along with the death of Pierce from the gunshot wound, Annie being institutionalized, Troy suffering throat injuries after trying to eat the Troll doll while it was on fire and Shirley's subsequent alcoholism dealing with the trauma from the event, causes Abed to declare this "The Darkest Timeline".
The label on the bottle of Serbian rum is written in Cyrillic script, the writing language and alphabet used in the Balkans and Northern Eurasia. It reads "ГEHEPИЦ PYM" which is the English phrase "Generic rum" transliterated to Cyrillic, which means Pierce probably overpaid for something he thought was a rare.