Evil Britta is an alternate version of Britta Perry, the product of a divergent timeline in which the study group suffered great personal losses. Devastated by those tragedies, the Abed of that reality dubbed this The Darkest Timeline, and suggested they become as dark and twisted as the reality they had to endure. In solidarity with the rest of the study group, Britta dyed a blue streak in her hair as she wasn't as traumatized by the event as the rest of her friends were. Her first appearance was in the Season Three episode "Remedial Chaos Theory". She is portrayed by Gillian Jacobs.
In the study group's third year at Greendale, Troy and Abed decided to move in to an apartment together. A housewarming party was thrown where the roll of a die created six different scenarios. In one alternate reality, Pierce supposedly died after accidentally being shot by Annie's gun, Annie was committed to a mental institution, Jeff lost an arm trying to put out a fire, Shirley began drinking again and Troy's throat was damaged. In solidarity to her friend's misfortunes Britta dyed a blue streak in her hair. Abed suggested they embrace the darkness and somehow find their way back to the "Prime timeline" they split off from and regain their former lives. He dubbed himself "Evil Abed" and suggested everyone assume similar monikers ("Remedial Chaos Theory"). Britta was reluctant at first but after Evil Abed's first cross-dimensional invasion failed ("Introduction to Finality") and "Evil Jeff" took over she decided to join the cause as Evil Britta.
Evil Britta Britta'd explaining how to win.
The second incursion into the "Prime Timeline" was led by Evil Jeff and Evil Annie. When their mission failed, Evil Britta, Evil Troy and Evil Shirley showed up equipped with Darkest Timeline paintball guns. The Evil Study Group searched the campus for their counterparts and wound up in the cafeteria. They were shocked by the return of their reality's Pierce who wanted to join them. Evil Britta told him the first person to shoot themselves, referring to the Prime timeline doppelgangers, won. Pierce misunderstood and got warped back to his reality after shooting himself with his paintball gun. Evil Britta accidentally shot herself too and got sent back to the Darkest timeline as well earning herself a sharp rebuke from Evil Jeff ("Advanced Introduction to Finality").
Evil Britta warps herself back to The Darkest timeline.