Penguins (refered by Dr. Princess as Smoking People) make their first appearance in the original short "Adventure Time," where Finn (known as Pen in the original short) and Jake use them as snow boards. Penguins live in the Ice Kingdom and they seem to like the Ice King, Finn, and Jake as they were seen tickling Ice King and riding on Jake in "Prisoners of Love." They are friendly creatures. However, some of the penguins work for the Ice King. In general, they don't seem to have many concerns or motivation, they will do what Ice King asks but are easily distracted.
Penguins appear in the episode "Prisoners of Love," as well as in the opening scene of every episode that plays during the Theme Song. Many penguins have their souls sucked by Hunson Abadeer in "It Came from the Nightosphere."
As of "Princess Monster Wife," it has been revealed that there are many distinct penguins which all have names pronounced similarly to "Gunter" (such as "Goonter," "Gunther," "Günter," and "Goonther").
In the episode "The Tower", Finn takes some penguins and uses them to create the tower along with parts of the Ice Kingdom.
They all have eyes that look similar to Jake's. Unlike real penguins, they have a head the same size as their body. Their backs are black and they have a white belly.
- Ice King doesn't seem to care much about most of the penguins he keeps in his company, as he throws several in the garbage after they bathe him in "Five Short Graybles."
- They are allowed to drink the Ice King's tears as seen in "Five More Short Graybles."
- Some penguins are allowed to vote what movie they want to play by the Ice King in "Another Five More Short Graybles."
- The concept of riding penguins may have been inspired by the pilot of Avatar: The Last Airbender.
- Oddly, penguins are often heard making quacking sounds, contrary to the sound of the emperor penguin in real life.
- Unlike many of the animals in Ooo, they did not acquire the ability to speak English after the Great Mushroom War.