They both have a lot in common, mainly because they're both stationeries and their large group of friends.
Since Pen did not qualify for BFDIA, their relationship did not expand,
Episodes suggesting a possible crush/relationship
- Take the Plunge: Part 1: Though this may be a coincidence, Pen is standing next to Pencil and her alliance on the balance beam.
- Take the Plunge: Part 2: Pen ends up on Pencil's team, courtesy of Pin. Also, when considering which of the male contestants to choose as per request of the Announcer, Pencil is among the consensus that approves Pen joining their team.
- Barriers and Pitfalls: Pen, along with Blocky save Pencil from being eaten by a fish.
- Cycle of Life: Pen carries Pencil during the challenge and Pencil looks really happy about it.
- Crybaby!: Pen and Pencil are right next to each other when their team turns into a snowball, though this may be a coincidence.
- Pen and Pencil nearly hold hands with each other when Snowball joins.
- A Leg Up in the Race: Pencil climbs the ladders directly below Pen. Also there is an error which shows Pencil hugging Pen when Eraser and Firey reach the top.
- In the same episode, Pen and Pencil are next to each other when Announcer gives them all 30 points.
- Don't Lose Your Marbles: When Pencil placed second in the scoreboard, right below Pen, she was very happy.
- Vomitaco: They're nearly holding hands when Bubble says "That's harsh!" at 1:44.
- Bowling, Now with Explosions!: In the puppets segment, after realizing they aren't cliff jumping, Pencil tells Leafy "Let's watch clouds with Pen!"
- Return of the Hang Glider: When Pencil wants Bubble to win, everyone except for Pen threatens to slap her.
- Yeah, Who? I Wanna Know: Pencil tries to impress Pen with her Leafy Detector.
- This, however, included Pencil talking to Pen with a sarcastic tone, so it in unknown of she tried to impress Pen, or was just poking fun of him.
- Pencil also called him 'Pen Pen', which is almost similar to her nickname, 'Pence Pence'. Though it is unsure if she was intentional or was being sarcastic.
Episodes suggesting a conflict
- Take the Plunge: Part 2: Along with Match, Pencil's face almost immediately changes when Pen and Eraser want Blocky on their team.
- Puzzling Mysteries: At the end of the episode, when Pen finds two pieces that fit together. Pencil scolds him by saying "Finally!"
- Insectophobe's Nightmare: During the contest, Pencil didn't care that Pen hit the tree, or that he was choking in pain.
- Return of the Hang Glider: Pencil randomly appears behind Tennis Ball, telling Pen to get over the fact that Dream Island has been stolen.
- In Rescission, two people submitted recommended characters for the next episode: PencilDitz (who recommended "Pencil & Pen's Baby" and MurielEpic (who recommended "PencilxPen", a combination of the two.) "PencilxPen" was rejected in favor of the other character "DNA".
- Pen and Pencil are the only other contestants to show their love for each other, along with Leafy and Firey.
- Pen and Pencil's relationship might be able to be grown upon since Pen has the most votes to join IDFB 2 so far. Of course, this would not happen if Pen doesn't have enough votes to debut. It appears as of now, Match had the most votes.