Agar.io is a free online survival action game developed by Matheus Valadares. In the game, players control a small cell on a simple map, with the main goal of swallowing smaller cells to grow in size, while avoiding being devoured by larger cells. Agar.io stands out for its simple yet strategic and competitive gameplay. The game supports online play with hundreds of different players on the same map, providing an engaging, thrilling, and addictive experience. It is an ideal game for quick entertainment, but also requires ingenuity and tactical thinking to survive in the long run.