Slither.io

Slither.io is a .io game about becoming the longest snake in the game The gameplay is very simple. Drag your mouse and the snake will follow it. (like most .io games) The neon circles you eat make you become longer. Players drop these when they die.

Characters
There are many characters, but all of them do the same things. Move, eat, boost, etc.

The characters come in different colours. Some have emblems or colour palette of some countries (EX: Russia for colour palette, Canada for emblem.)

Some also have profile pictures of famous YouTubers that play the game. (EX: PewDiePie, Jelly, Jacksepticeye)

There is also a skin creator to create your own skin.