Spectator Spirits is a server-side mod adding a special way for spectator mode players to interact with their servers. When in spectator mode, you act as a spirit, with a trail of soul flames so others know of your presence. Pressing a number key from 1 to 3 selects a unique way of assisting other players. Such ash:

Healing

Luck Boost

Resistance Boost

Pressing up key while around living players applies the selected buff.

Modpacks and servers may use this, but redistribution is strictly forbidden.