Rinse the sushi rice under cold water until the water runs clear. Combine the rinsed rice with 1 1/4 cups water in a pot and bring to a boil.

Reduce heat to low, cover, and simmer for 15-20 minutes until the rice is cooked and all the water is absorbed.

In a small bowl, mix 1 tablespoon rice vinegar, 2 tablespoons sugar, and 1/2 teaspoon salt until dissolved. Stir this mixture gently into the cooked rice.

Allow the rice to cool to room temperature.

Lay a sheet of plastic wrap on a sushi mat or a clean surface. If using nori, place it shiny-side down on the plastic wrap.

Spread a thin, even layer of sushi rice over the plastic wrap or nori, leaving a 1-inch edge uncovered.

Place fillings (4 flattened marshmallows, 1/2 cup Fruity Pebbles, and 1/4 cup gummy candies if using) in a line across the rice.

Carefully roll the sushi using the mat or plastic wrap, pressing gently to form a tight roll.

Slice the roll into bite-sized pieces with a very sharp, lightly wet knife.

Serve immediately as a fun, colorful treat.