The Vitality Mod is where you start at 1 heart and when you die, you gain an extra heart. When you die at full health (10 hearts), you are kicked from the server and cannot rejoin.
Based off of https://www.youtube.com/watch?v=VkU8AP0dC9A
#####2022-17-10 - The rejoining bug to set 1 heart is fixed.
balanced hardcore
not for servers though