Fisty's Bog is a level in the video game World of Goo. It is the ninth level of Chapter 1. The name "Fisty's Bog" refers to Fisty, the large gray frog seen in the level. In Fisty's Bog, the player must use Black Goo and Balloon Goo to cross through an area with spikes on both the floor and ceiling. This level deals with finding an equilibrium between two opposing forces: gravity and buoyancy.
A sign found on this level says "Fisty swore he would never be like those tadpoles that grow up and shoot colored gems out of their mouths." This is a reference to the video game Zuma, made by PopCap Games.