Minecraft after death in Spectator mode?

With which command you get, when you die, in the Spectator mode

Change the version to spiggot and install the plugin script because you can ggaaanz simply write plugins for you would need something like this:

on death:

set gamemode of% player% to 3

send:% player% has died!

Is this synonymous on a forge server?

Maybe there's a plugin that I can install there