I had to do this project twice to get the hang of it. The first time I bought cups that were a bit wide and fancy balloons that were a bit thick and hard to stretch. I went back and bought another set and did cheap balloons and smaller cups. That was far easier to do. My son thought this was particularly hysterical. Who doesn’t love making a mess. 

WHAT YOU NEED: 

Plastic Cups (Small/Medium size and sturdy. Wimpy cups will crush under the strength of the stretched balloon)

Balloons

Marshmallows (or pom-poms)

Sharpie 

Xacto Knife (for adult)