Evil Shirley is an alternate version of Shirley Bennett, the product of a divergent timeline in which the study group suffered great personal losses. Shirley herself was heavily traumatized by witnessing the death of Pierce Hawthorne as she was sprayed with his blood and fell off the wagon, becoming an alcoholic. 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. Shirley was largely indifferent to his plans although she accepted one of the felt goatees he passed out as a symbol of the group's new evil purpose. It's assumed that she later agreed to take part in the plan when Evil Jeff declares after Evil Annie's trial that he and the rest of the "Evil study group" plot to destroy the "Prime timeline". Her first appearance was in the Season Three episode "Remedial Chaos Theory". She is portrayed by Yvette Nicole Brown.
In the study group's third year at Greendale, Troy and Abed moved in together. At the housewarming party 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, Troy's throat was damaged and Shirley began drinking again. Abed suggested they embrace the darkness, 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. Shirley was far too inebriated to seriously consider Abed's plan and put the felt goatee on a beer bottle she was drinking out of ("Remedial Chaos Theory"). When Evil Abed's first cross-dimensional invasion failed ("Introduction to Finality") and "Evil Jeff" took over Shirley decided to join the cause as Evil Shirley.
Evil Shirley dazed and confused.
The second incursion into the "Prime Timeline" was led by Evil Jeff and Evil Annie. When their mission failed Evil Shirley, Evil Britta and Evil Troy arrived there 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. Unexpectedly, both he and Evil Britta wound up shooting themselves and they were sent back to The Darkest Timeline. The other Study group made their presence known and once the battle began Evil Shirley shot wildly and completely missed her doppelganger. The Prime Timeline Shirley told her to get some help before warping Evil Shirley back to her own reality ("Advanced Introduction to Finality").
Shirley sends Evil Shirley back to the Darkest Timeline.