Advanced Introduction to Finality - S4-E13
Continuity mistake: In episode 11 of Season 4, it was stated that Leonard got an A in 1968, then opted for pass/fail to have the highest GPA in the college. In the final scene of this episode, however, it shows Greendale college as being established in 1974.
Answer: His attempt to "kill" Jeff was to roll at him as an iPad on a stick. He knew it wouldn't work, but it played to the story that he was a killer as he knew Jeff would tell people about it, or attempt to retaliate for it.