Grease

Grease is one of the main overarching themes in the Wafanci, probably even more so than love and friendship. The grease in the story symbolizes greasiness and stink.

Lore
It is told that the universe was created in a cosmic explosion called the Grease Bang. First, there was nothing. Then there was a fuck ton of grease and Mr. Hakanen. Or that is the theory anyway. This event is hypothesized to be the origin of all grease. As Yoda put it, grease cannot be destroyed nor created, only transformed.