Preheat oven to 375ºF. Spray a cookie sheet with cooking spray or line with parchment paper.
Unroll crescent dough and separate each triangle.
Have children dip marshmallow in water. Roll in cinnamon and sugar mixture.
Place marshmallow in the top of the crescent roll and roll into a crescent roll shape, then secure the sides by tucking them under and pinching them closed. (Don't worry about how they look! They will be yummy!)
Place on prepared cookie sheet and repeat with remaining 7 rolls.
Bake in preheated oven for 8-10 minutes or until golden brown on the outside.
Let cool for a few minutes and then let the children pick a roll to open up. The marshmallow has disappeared!