Growtopia is a 2G massively multiplayer online game (MMO) that allows the player to do pretty much everything he wants, from building houses to creating puzzles for other users to solve. This "sandbox" developed by Ubisoft distinguishes, for example, from Minecraft in that it can create things like songs, drawings or levels, among others.
The possibilities within Growtopia are immense, and in the course of the main game you will find thousands of mini-games. This sandbox allows you to interact with other players, including visiting the worlds they have created.
Growtopia is cross-platform, meaning that by creating an account you can access your game on Windows, Mac, or iOS. It can be installed for free through Google Play or the App Store.