"Gets Eaten" is the fourth episode of season one of the animated children's series The Magic School Bus. It originally aired on October 1st, 1994.
Arnold and Keesha were supposed to do a "Two-Things-That-Go-Together-Report," but they both completely forgot about it. Keesha only brings a tuna fish sandwich, and all Arnold brings is "scum" he got on his shoe when he stepped in a pond on his way to school. The two don't have anything in common...or do they? Ms. Frizzle takes the class on their beach trip, but once there, it quickly becomes a field trip when she shrinks the bus to explore the ocean food chain.
The students are prepared to go to the beach this afternoon for their Two-Things-That-Go-Together-Report. Dorothy Ann and Carlos brought a crab and sand, Phoebe brought a tube grass in a pot, Ralphie brought the sun (which is really a yellow balloon), and Tim and Wanda brought portraits of mussels. When Keesha enters the classroom and is reminded of the report, she panics when she doesn't have anything to bring for the report other than a tuna fish sandwich. Just then, Arnold enters the classroom and is shown to have stepped in a pond on his way to school. He, too, had forgotten all about the report and hasn't brought anything either. The rest of the class get an idea, but later reject it when they realize that tuna and scum don't go together. Just when Arnold is ready to quit, Keesha tells him that the two have to work with what they have. Mrs. Frizzle enters the classroom to discuss the report. Wanda and Ralphie are first to present their report, and to Keesha and Arnold's dismay, Mrs. Frizzle calls them up to present their report. So the two show her the tuna fish sandwich and the scum on Arnold's shoe. To their surprise, Mrs. Frizzle tells them that it is fantastic. She asks them to explain how the two objects go together, to which Arnold hesitantly responds that they both have adjectives. Just then, the bell rings, and Mrs. Frizzle takes the students to the beach.
During the bus ride, Arnold and Keesha have a conversation on the work they have to do for their report. They conceive ways on how each of their items complement each other. Mrs. Frizzle overhears heir conversation and tells them that it is up to them to look for connections. The buss finally arrives to the beach. Once there, the students view the things that they had for their report. A seagull then flies down and grabs the crab with its beak right before flying back in the air. While Arnold and Keesha think of ways the sandwich and the scum go together, Mrs. Frizzle arrives via bus and picks up the rest of the students. Once everyone hops inside, the school bus transforms into a fishlike figure and dives into the sea.
The school bus then transforms into a boat and it continues floating in the sea. Keesha and Arnold are still thinking about their report. The students take a look down to the glass floor to view seaweed and sea urchins underwater, the latter of the two eats the former. A sea otter then swims down to take the urchins. When Arnold looks through the floor to view green slime, Wanda says that it's "scummy", giving Arnold an idea. Mrs. Frizzle uses a fishing net to scoop up the green scum and tells the students that it is phytoplankton, which are tiny plants. Mrs. Frizzle then offers Keesha her modeled magnifier to view the phytoplankton up close. She finds sea scum on the phytoplankton in the net and shoe scum of the phytoplankton on Arnold's shoe. When Kesha agrees with Mrs. Frizzle that they should take a closer look, the bus shrinks down to a microscopic submarine and dives underwater. Mrs. Frizzle offers the students underwater breathing gear and they explore through the underwater sea on a search for connections. They come across a pink sea creature, who eat phytoplankton. Mrs. Frizzle rescues them and brings them back on the bus. She then expands the bus' size so that it would be just as big as the pink sea creature, which is called the zooplankton. The students swim back into the sea to search for connections. They then come across some anchovies (which Ralphie states that they're the same kinds of anchovies that his father pulls off his pizza). They also learn that anchovies eat zooplankton, which Mrs. Frizzle states leaves them to lunch. They return inside the bus, which changes to the size of the anchovies. During lunch, Keesha asks Arnold what is inside a tuna fish sandwich, which Arnold responds with tuna fish while explaining the other ingredients, which gives Keesha an idea. The bus then come across a tuna, which eats anchovies. The tuna then proceeds in eating the school bus as well.
The school bus is now inside the tuna and Keesha tells Arnold that they had finally found the connection to their report: phytoplankton gets eaten by zooplankton, which gets eaten by anchovies, which gets eaten by tuna. As a result, tuna and phytoplankton belong in the same food chain. Mrs. Frizzle also tells the class that they are now studying the tuna's digestive system. But she decides to leave it for another day so Keesha and Arnold can present their report and successfully manages to exit the bus out of the tuna using a fishing hook, which reels in the bus. The fisherwoman takes the microscopic bus and throws it back into the sea. It then changes to a wide surfboard and Mrs. Frizzle and the students surf to shore.
Back in school, Arnold and Keesha present their report on the ocean food chain. Carlos compliments the report, saying that it's so "e-fish-iant". Mrs. Frizzle then presents the class a land food chain, where a mouse eats grass seed, a snake eats the mouse, and a hawk eats the snake. The hawk is at the top of the food chain while grass is at the bottom. The class then learns that phytoplankton and grass are both plants, for all food chains begin with plants. Arnold then realizes that his shoe is missing. Back inside the ocean, the tuna coughs up the microscopic shoe, which is caught in the fisher's hook. As the fisher reels it in, she tosses it along with the other junk in her boat. A hawk then swoops down and grabs it with its beak and drops it down to the school. The shoe doubles in size and lands in Arnold's hands. Arnold states that "Nature never ceases to amaze me", to which Mrs. Frizzle responds "If the shoe is clean, wear it", which elicits laughter by the other students.
- Keesha says "Oh, bad, oh, bad, bad, bad, bad!" for the first time.
- Arnold says "I knew I should have stayed home today" twice in this episode.
At the end of the episode, when everybody is laughing, Ms. Frizzle is wearing a green dress. When the camera zooms out, she's wearing a purple one.