Slither.io

Slither.io is an online multiplayer video game. It is played on a web browser or through an app. The game was started by Steve Howse in 2016. 
The game is played in the role of a snake eating 2-dimensional glowing dots on a grid. It is based on the 2015 game Agar.io, with the main difference is that snakes will die when their head collides with another snake, instead of being based on size like in Agar.io.
The game is most played in multiplayer , where every snake is a human player. In the iOS and Android versions, however, it can also be played in singleplayer, where every snake except the player is controlled by the device.