For eample we have a server. And we have two types of users - players and spectators.
How can i make spectators invisible for players and for other spectators - semitransparent?
Sadly this capability is not available to developers yet so we can not create a plugin. We can make the player vanish completely but not to some.
We need this added into Sponge for us to develop plugins to do that. https://github.com/SpongePowered/SpongeAPI/pull/1046