During the episode, Bart attends a rap concert without permission so Lisa and Principle Skinner use footage of the rapper's chain to prove that Bart actually attended the concert.
The meme began spreading back in 2014 when a Reddit user posted a screenshot of the rapper to /r/TheSimpsons with the caption, "Happy Thursday the 20th, everybody!" Ever since then, anytime it's Thursday the 20th, this meme shows up in full force.
In 2017, Thursday the 20th occurred on the same day as famous stoner holiday 4/20 so the image was photoshopped to make the rapper appear high.
Here's a clip from the episode:
Here's a list of all the days Thursday the 20th occur for the next 10 years so you can be prepared:
|2020||Thursday, February 20, 2020||February||+ 8 months||2 times in year 2020|
|Thursday, August 20, 2020||August||+ 6 months|
|2021||Thursday, May 20, 2021||May||+ 9 months||1 time in year 2021|
|2022||Thursday, January 20, 2022||January||+ 8 months||2 times in year 2022|
|Thursday, October 20, 2022||October||+ 9 months|
|2023||Thursday, April 20, 2023||April||+ 6 months||2 times in year 2023|
|Thursday, July 20, 2023||July||+ 3 months|
|2024||Thursday, June 20, 2024||June||+ 11 months||1 time in year 2024|
|2025||Thursday, February 20, 2025||February||+ 8 months||3 times in year 2025|
|Thursday, March 20, 2025||March||+ 1 months|
|Thursday, November 20, 2025||November||+ 8 months|
|2026||Thursday, August 20, 2026||August||+ 9 months||1 time in year 2026|
|2027||Thursday, May 20, 2027||May||+ 9 months||1 time in year 2027|
|2028||Thursday, January 20, 2028||January||+ 8 months||3 times in year 2028|
|Thursday, April 20, 2028||April||+ 3 months|
|Thursday, July 20, 2028||July||+ 3 months|
|2029||Thursday, September 20, 2029||September||+ 14 months||2 times in year 2029|
|Thursday, December 20, 2029||December||+ 3 months|