Agma.io is a free multiplayer online game. It is a version of cells eat cells game with far more features than the normal. It includes extra things such as power-ups, secret rooms, secret commands in chat to make your cell appear differently and animate, friendslist, private chat with friends, squad up with team members, tournament battle royale gamemode, and a lot lot lot LOT more. You start the game off as a small circle, surrounded by pellets which you can eat, green viruses (which split you into small pieces and make you vulnerable), and other players. You can use the space bar to split into twice as many circles, but you keep the same mass. If you press W, some of your mass gets shot out. If you feed a virus, it will shoot out another virus. When aimed at a player, you can use the virus to make a player more vulnerable. There is a leaderboard which shows how big you are as a number. Number 1 is the biggest player, higher numbers are smaller players. If you make an account on agma.io, you can save your progress so that you continue to grow each game.
The more mass you gain, the more you level up, which allows you to wear new skins.
You can invite other players to parties, which is where you can see each other on the map and have a special party chat to discuss strategies, plans, or whatever you desire.
This game is very addictive and I would highly reccomend it.