The Grass People are characters who appear in "James Baxter the Horse." Finn and Jake encounter some sad-looking ones when looking for people to test their "feel-good sounds" on. Jake asks them what is the matter, and one Grass Person responds, "We're bummed." Jake shape-shifts into a trumpet and Finn "plays" him, which cheers them up. They later come across a Grass Person nervously giving a speech about beetles to an uninterested crowd of Grass People, Rock People, and Tree People, whom Finn and Jake also cheer up.
Grass People come in a variety of shapes and sizes. Some are blades of green grass, while others are clumps of soil with grass for hair. The grass roots form their arms and legs. The one giving the speech about beetles has a yellow flower growing on top of his head.