In a large saucepan on low, melt butter, add marshmallows. Cook until melted stirring often, about 5 minutes.
Add rice crispy cereal to melted marshmallow and stir to combine.
On a flat work surface unroll the fruit roll-ups on the plastic wrap they come in. Scoop out about 1/4 of rice crispy treat mixture (while it's still slightly warm) and spread it evenly on 3/4 of each fruit roll-up. Place one twizzler and one sour straw in the middle of each. Roll up tightly. chill for 5 minutes.
Cut off the ends with a sharp knife, then slice crosswise into 6 pieces.
You can really use whatever kind of candy you like, the sky's the limit...have fun!