Paper Slips are magical pieces of paper in the world of BFDI that turn into dollar bills when a number is written on them. The commercial for it is shown in Crybaby! and has been used several times by Pen and Leafy.
It is used like a money bill, except you can write numbers on it, and the paper slip will have the worth of that number.
- Vomitaco: Pen asks how much he has to pay for Leafy to lend him a taco, and the answer is such an expensive price of 200 vigintillion dollars. Pen says "Well, what do you know?" while holding up a dollar bill with the price in one hand and the box of paper slips in the other. Unfortunately, this makes the eliminated contestants know he cheated, making him fall into the danger zone and, ultimately, eliminating him.
- Gardening Hero: His re-campaign speech is if someone votes for him, the voter will get 500 million vigintillion dollars while holding the paper slip containing so. However, in the next episode, after he learns he didn't get enough votes, he recite the usernames of the people who voted him and says "I owe you 500 million vigintillion dollars each because I can't afford to pay you right now" before getting teleported to the TLC again.
- Return of the Hang Glider: The Box of Paper Slips play a key point in this episode. After Firey rejects Leafy from Dream Island, Leafy calls up the Announcer and gives him $1,000,000,000,000 drawn on a paper slip to buy Dream Island to get revenge on Firey, which leads to the plot hole of this episode. In the end, when she almost dies, Firey saves her with a hang glider and reveals his true feelings for her.