Learn Java, code Minecraft plugins and launch a unique network from the ground up in 20 days (without experience):
Boss is a premium quality plugin for custom monsters on your server.
You are welcome to read the Boss Wikipedia, where you will find tons of information about the installation, configuring and using this plugin.
If you have any questions or bugs to report, you are welcome to fill an issue. Please read the Getting Help the Best Way to obtain help as quickly as possible.
Get it here: https://www.mc-market.org/resources/21619/