Crystal is one of the youtuber skins in Agar.io. It can be used by typing "Crystal" in the nickname box before starting the game. Then the player's cell will become the logo of the TψT Clan's co-leader, Crystal. Crystal's real name is Simon and he's German.
The Crystal skin has been added on October 27th, 2016 along with 7 more Youtuber skins :