M&M's are colorful, bite-sized chocolate candies featuring a hard sugar shell with a lowercase "m" printed on each piece, known for their milk chocolate (or other fillings like peanut) and vibrant coatings that prevent melting, making them fun for snacking, parties, and baking. Developed by Forrest Mars Sr. and Bruce Murrie during World War 2, the "M&M" stands for their names, creating a chocolate treat that's both delicious and easy to share, with variations from minis to peanut butter.