| Please note the following:
- "Jeffy Skips School!" is the 428th episode of SML Movies.
The episode starts off in school with Jackie Chu teaching the class math lessons about egg rolls. He gives the class homework and Jeffy refuses to, and decides to do a Fortnite All-Niter, with Junior and Cody agreeing. Mario comes and tells Jeffy to do his homework, but Jeffy refuses. While Mario uses the bathroom, Jeffy answers the door after hearing the doorbell ring. He finds Dr. Brooklyn T. Guy with Harold Wilfred, Mario’s grandfather, who was kicked out of his retirement home after grabbing a nurse's (Veronica) butt. Finding a good opportunity to trick his dad once again, Jeffy switches clothes with Harold and goes to his closet, where he remains for the rest of the night.
After helping the disguised Harold with Jeffy's homework, Mario sends him to bed. The next day, Jackie Chu begins teaching the class about the Pearl Harbor attacks, claiming that they were all accidents, as the Japanese simply wanted to fly to Hawaii, but ran out of gas mid-flight and crashed into the harbor. After exchanging several insults with the slant-eyed teacher, Harold is suspended from school for deliberately saying "carrots" when told not to speak again. Angry at who he believed to be his son, Mario demands that Harold takes out the trash.
After confusing a flight of stairs for an elaborate trap made by the Nazis, Harold dies after trying to jump said stairwell. Distraught, Mario calls Dr. Brooklyn T. Guy, who instantly recognizes Harold. This confuses Mario, who believes that anybody wearing similar clothes to Jeffy's are Jeffy. After the true Jeffy comes out of the closet and asks for a pizza-related food, Mario becomes even more confused, angering Brooklyn T. Guy further.
- Bowser Junior
- Harold Wilfred
- Jackie Chu
- Brooklyn T. Guy
- Bully Bill (Non-Speaking Cameo)
- Joseph (Non-Speaking Cameo)
- Luigi (mentioned)
- Veronica (mentioned)
- This marks Harold Wilfred's first appearance in 2019 and first appearance since Jeffy's Home Alone!
- It is heavily implied that Mario suffers from Prosopagnosia, a neurological condition characterized by the inability to recognize the faces of familiar people. This could explain why Mario always mistakes Jeffy imposters for the real deal because he only remember people by their clothes. Bowser could also have prosopagnosia since in Chef Pee Pee Gets Sick! and Pop Rocks and Coke! he thinks Bowser Junior is Chef Pee Pee since Bowser Junior was wearing Chef Pee Pee's clothes.
- This is Jackie Chu’s third appearance in a row.
- This is the third school-series episode in a row.
- It is unknown if Harold dies or was unconscious in the end, even though Mario said that he wasn't breathing.
- Before going to bed, Harold says "anal", this is what Jeffy said when Mario woke him up the previous video, Jeffy's Teddy Bear!.
- Mario doesn't recognize or pay attention when Black Yoshi disguises as Jeffy, just like in Jeffy's Lunch Money!. Coincidentally, Brooklyn T Guy is on the scene in both videos and says what the next video is, both involving Mario's eyes (Mario Gets Glasses and Mario Gets Eye Surgery) .
- Although Jackie Chu is mostly Chinese, he refer himself as Japanese while teaching about Pearl Harbor to his class.
- Mario was able to recognize Jeffy without his shirt on no problem in Jeffy Gets Expelled!, but here he finds him unrecognizable. However, this could likely be due to the fact that Jeffy didn't have his helmet on either.