The short begins with Dipper saying he'll be studying Gravity Falls anomaly #42, "The Tooth," and points out a massive molar Mabel is poking with a stick, she then states she was there for scale. Dipper says he found it while he was practicing the sousaphone. He later asks Tate McGucket about it. He says he doesn't know about it, but warns him to run if he sees bubbles in the water.
Later that night, Dipper and Mabel go out onto the lake with a rowboat to investigate. Mabel brings her childhood puppet Bear-O, and Dipper protests by saying Bear-O is creepy and everyone hates him. To support this, a clip is shown where Mabel's Bear-O puppet show traumatizes a group of kids. Mabel ends up having to leave Bear-O at the shore. Shortly afterwards, Mabel produces a pro-Bear-O ad.
Soon, the twins notice bubbles in the water near a small island. The ground starts to shake, and the twins begin to row away. As they do this, the island floats out of the water, revealing it to be a giant floating head. The camera shuts off as the head approaches the rowboat.
The camera is later found on the beach. Dipper says the giant head thing sunk back into the lake after it attacked, and it lost another tooth trying to eat the boat, but the important thing is that they survived, barely. The short ends when Mabel pulls out Bear-O and says "Did somebody say BEARLY?" which scares Dipper.
- Dipper can play the sousaphone.
- Mabel owns a hand puppet named Bear-O.
- Tate McGucket apparently knows about some of the mysteries of Gravity Falls.
- Mabel wears her seahorse and bubbles sweater from "The Deep End."
- In the flashback featuring her song, Mabel wears her striped sweater first seen in the "The Time Traveler's Pig."
- Dipper mentions his and Mabel's previous encounter with a lake monster.
- When played backwards, the "floating island head" says, "You have awoken me from my slumber! Enter my mouth, children! Enter your destiny! RAAAAHH!"
- In a scrapped episode, it was supposed to be revealed that Dipper is afraid of puppets. In this short, he seems uneasy around Bear-O, suggesting that this may still be true, however this may have been a fear he has gotten over as in "Sock Opera" he doesn't seem to mind puppets.
- In the Latin American version, the island says "Una nueva era comienza, 6 1 8, la nueva era 6 1 8." meaning, "A new age starts, 6 1 8, the new age 6 1 8."
- The same thing is said when the German version is played backwards.
- Also, in Russian version the island says "Начинается новая эра. Шесть-один-восемь, шесть-один-восемь!" meaning "The new era is coming. Six-one-eight, six-one-eight!"
- The giant tooth in this short is also an obstacle in The Great Stanmobile Escape.
- At the end of the short, another section of the hidden page flashes briefly with a cryptogram at the bottom of the page. That reads, "FRGHV RI FUHGLWV SDVW RQH PHDQV RQH VR VHDUFK." Once decoded, it reads, "CODES OF CREDITS PAST ONE MEANS ONE SO SEARCH."
- The codes made from red numbers decodes to "KNESS IS."
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