Stethoscope is the object world's resident doctor, and she tends to bring it up whenever she has the chance. She is very good friends with Beach Ball, and she has a special landing pad she uses to help him get his bouncing under control.
In How It Began, Stethoscope used the landing pad for the first time to stop Beach Ball's bouncing. This was after Beach Ball was picked onto Water Balloon's team. Stethoscope herself was later chosen to be on his team.
During the contest, Stethoscope crossed the river and placed a landing pad on the ground. Beach Ball landed on the pad shortly afterward.