- In an episode of I'm a Marvel... and I'm a DC it featured Batman and Iron Man trading barbs about each other's movies. At the end, Batman proclaimed that Iron Man has herpes. After a year, Jonah Hex and Iron Man were trading barbs about each other's movies.Jonah: * cough* Herpes * cough*Iron Man: What?!
- One of Matt Santoro's videos is called 20 Ways to Lose Your Man Card, which lists 20 ways to lose one's man card, a symbolic representation of one's manliness. In a later video, Mail with Matt #3, Matt gets sent a physical man card from a fan in the mail. Matt is quick to explain the continuity nod to the audience.
- Don't Hug Me I'm Scared
- In the second video, there is a line that clearly sets up a rhyme in "green", but Tony uses "brown" instead. Why? Because, of course, green is not a creative colour.
- Yellow Guy's clown painting (Still ruined by black paint) appears in the sequel to the original video, and yet again in the fourth video.
- The craft that Yellow Guy made in the first video appears in the third.
- In episode 2, the students meet a talking clock named Tony who teaches them about time... and causes them to age so rapidly their bodies rot away. In episode 4, when Colin the Computer brags about being able to tell time, Duck Guy looks at the camera with concern as he says "Time?!" In episode 6, Yellow Guy is horrified when Tony briefly appears again, telling him "You made me die!"
- In a Foil, Arms and Hog sketch. Intended in Ceoil agus Ól 2, with the reference to the Ferrari, but Foil and Arms roles were unintentionally switched.
- Entirely Presenting You: There's a lot throughout the series, but the most notable one is in the first arc, where the first and last chapter mirror each other in both events and writing.
- The Green Wanderer (which is set in the same universe as Smirvlak's Stone) has a small line from Mulvernt where he mentions he gave two goblins and a stilio a ride to a castle. Said goblins and stilio were Nick, Gnek, and Stilyk, the main characters from Smirvlak's Stone.
- The Misadventures of R2 and Miku has a surprising amount of these, despite liberally employing the Snap Back:
- Miku eating a squirrel in "R2 and Miku Stuck in a Treehouse" leads to her getting sick in "Disease".
- "Clones" ends with Miku realizing she's come back from death before, citing her death in the treehouse and murder by the cow from two prior episodes.
- "The Chimp" opens with Miku laying despondently in bed, leading R2 to assume she got sick like in "Disease".
- Upon seeing a depressed Miku in "Miku Hits R2 with a Chair", GLaDOS asks if she's still sad over Croatia's loss in The World Cup (as was the case in "The Chimp"). At the end, R2 hears about a "pizza delivery cow" and immediately makes the connection to the one that shot him dead in "Disease"; Miku's failure to connect the dots ends up proving fatal once more.
- Tails of the Bounty Hunter has a short moment in chapter 8 where Yordin mentions "the Universal Gardens Massacre" that happened several years ago. Said massacre and the events leading up to it are shown in full detail in Tails of Fame.
- Episode 15 of World's Greatest Adventures mentions the Aztec Pinecone of Gold from Episode 3, and Episode 23 brings back the sets of Episode 15, Episode 16 and Episode 22.
Continuity Nod / Web Original