Early in development, there was going to be an enemy named "Tramplin' Stu", another iteration of Stu in the game. The Tramplin' Stu was supposed to spawn Swoopin' and Strollin' Stu behind it as it walked. To defeat a Tramplin' Stu, you must fill it with water so that the outer shell pops, then you stomp on the eye on top of it. The data for Tramplin' Stu can be found in a test map where it shows up correctly, but without its shell. Tramplin' Stu shows up correctly with its shell when moved to the Delfino plaza map.