Agar.io is a massively multiplayer Web Game created on April 28, 2015 by at-the-time 19-year-old Brazilian developer Matheus Valadares as a browser game before expanding to Steam on May 3, 2015, and later to Android and iOS devices on July 8, 2015.
It is a multiplayer Rising Up The Food Chain Game: players control a cell on a map akin to a petri dish, and the goal is to gain as much as mass as possible by eating other cells and avoiding being eaten by other cells. It's more interesting, more intense, and more fun than it sounds, and was the subject of some quite monstrous popularity and success largely due to word of mouth to the point of being featured in an episode of House of Cards (US).
This game provides examples of:
- Advancing Boss of Doom: Any cell that is bigger than your cell can kill you. Especially applies to the really big cells chasing down smaller cells.
- Advancing Wall of Doom: Battle Royale mode has a red danger zone which continuously constricts the arena. Players who go into this zone get broken up and start shrinking.
- Anyone Can Die: Downplayed in comparison to Slither.io. In this game, you can only be eaten by cells bigger than you, so once you're the biggest on the board, you're pretty much invincible (provided you don't run into a virus and explode into dozens of smaller cells); others have to either feed a virus and push it into you, or beat your size by eating each other. It is very much this when you first start on the path of growth, though.
- Battle Royale Game: A special game mode where twenty players face off against each other, where players have to avoid being eaten by other players and the red danger zone.
- Easter Egg: Picking certain names will change how your cells look. For instance, picking the name "4chan" will change your cell into a pink cell with a four-leaf clover as the image.
- Everyone Chasing You: If a cell is bigger than you, they're going to chase you. If everyone is bigger than you, everyone will chase you.
- Hello, [Insert Name Here]: Players are allowed to name their cells, which of course leads to people picking interesting names.
- Hoist by His Own Petard:
- Sometimes cells feed viruses to make them grow and eventually split. However, if those cells don't back away quick enough, they themselves can run into the viruses.
- Also occurs when tiny cells split big ones by feeding a virus and pushing it into them. A large piece of cell is fired in the direction the virus was fired from.
- Nice Job Breaking It, Hero: When cells 'team', the smaller one sometimes gets the bigger one so big they are trapped and can be eaten easily.
- Rising Up The Food Chain Game: One of the archetypal examples of the trope.
- Trope Maker: The .io web games have started to pop up en-masse after the initial success of this game. This is done both to capitalise on the player familiarity, and because .io is the domain of the British Indian Ocean territories, and is one of the cheapest domains out there.