Bug milk is a key ingredient in gaining access to the Nightosphere. It appears in the episode "It Came from the Nightosphere," when Finn tries to reunite Marceline with her father. It is revealed in "Daddy's Little Monster" that Bug Milk is potable, as Hunson Abadeer is seen drinking it.
The bug milk is contained in a half gallon milk carton, and the color of the box is blue. The container has two symbols on the side: a ladybug near the top and what looks like a stool for sitting on while milking the bug. This suggests that a certain kind of bug is milked to get bug milk.
- It is possible that "bug milk" is a reference to the 1988 comedy horror film Beetlejuice.
- It may be related to beetle butter, which is seen in "Card Wars."
- It can be used as a power-up in the Adventure Time DS Game "Adventure Time: Hey Ice King! Why'd you steal our garbage?!!"
- As shown in "Sad Face," bug milk is drunk by other bugs, like ants.