https://store.steampowered.com/app/1197060/FUNGI/

FUNGI is a strategic online multiplayer game in which you battle the rest of the world. Grow from a single cell into a multicellular fungus by leeching mass from other players. You move around by placing new links and transfer energy from cell to cell. Fend off attacks and try to conquer the map whilst keeping your network intact. There are multiple ways to defend, attack or avoid others and there are a couple of powerups to help you along the way. With the right strategy even smaller fungi can be a threat, so watch out!

Activation Instructions:

1. You need to download and install Steam http://steampowered.com/download/SteamInstall.msi
2. Go to your account or register a new one.
3. Go to the "My Games" and select "Activate via Steam ...", and enter the key received after payment.
4. Once activated, the game will appear in the game list (Library) and you can download it