Volume 3, Episode 15: Jackson tries to resurrect his unmemorable evening after waking up by the school fountain with a chilling feeling that he—or more likely Holt—had a wild fright.
The alarm clock wakes Jackson from his peaceful slumber. As he puts on his glasses, he is horrified to notice his hands are covered in a red substance - paint. Even worse, when he tries to wash the stuff off his hands, it does not come off no matter how badly he scrubs. Jackson opts to hide his hands as well as he can when he goes to school.
At school, something has everyone talking and Frankie shows Jackson that someone vandalized the school with red paint. Jackson takes his paint-stained hands out of his pockets and explains that Holt must have done it. The two conclude that if Headless Headmistress Bloodgood finds out about this, Holt will be expelled and therefore Jackson too. And even aside from that, Frankie refuses to believe that Holt would just go and vandalize Monster High. They agree to uncover the truth of what happened, which is a mission not made any easier by the need to avoid Bloodgood at all cost. As it turns out, none of their fellow students have seen a thing, but the custodian, Mr. Ogrethor, has. He confirms that Holt was carrying paint out of the back of the school last night.
Jackson and Frankie Stein retreat back to the vandalized wall, wondering what they should do now that they have confirmation that Holt is fully responsible. Headless Headmistress Bloodgood shows up as they talk and tells Jackson she has to speak with him about Holt. Out of ideas, Jackson readies himself to accept the consequences of his counterpart's actions. However, it turns out that Holt was commissioned to paint a mural on the wall, but had to stop when Ogrethor, who can't stand loud noise, turned off his music, thus changing Holt back to Jackson. Bloodgood turns on a stereo to turn Jackson into Holt again so the latter can finish the mural, which ends up being a painting of Nightmare.
- The webisode's title is a play on the 1973 novel and its 1997 movie adaptation I Know What You Did Last Summer.
- The webisode's title, "I Know What You Did Last Fright", as "fright" is a pun on "night".
- The red paint covering Jackson's hands is a literal play on the phrase "caught red-handed", which is used to imply that a person was caught with the evidence on them therefore confirming they were guilty of doing the act.
- Jackson paints and draws in the Monster High book continuity. Jackson's and Holt's skills and knowledge are capable of seeping through to the other.
- Jackson's and Holt's room is seen for the first time.
- Ogrethor makes his cartoon debut. With this debut, he also makes his last appearance.
- Why does Jackson question if the vandal is a monster if he knows Holt did it and says so a moment later?
- Jackson's hands lightly vary in the amount of paint covering them throughout the webisode. When Holt makes his appearance, he even has only fragments of paint on his hands. Furthermore, after Frankie tells Jackson to "bolt" when Bloodgood searches for him, he has no paint on his hands at all.
- The background of Frankie and Jackson asking Cleo, Lagoona, and Clawdeen if they've seen anything doesn't line up with the background of them saying they haven't, nor is the way the three girls are standing together the same between shots.
- The webisode implies that Holt ceased to be active the moment Ogrethor turned off the music. However, if that's the case, then how did Jackson get home without noticing the paint earlier?
- The black and white on Holt's shirt reversed sides, the second time this has happened, the first being "Hyde and Shriek".