This plugin is actually for 1.19 and above. However, it has been adapted to version 1.12.2.
This add-on creates a zombie clone after players leave the server.
Quote descriptionı:
"OfflinePlayers is a plugin that creates an entity when player participation is interrupted. These entities can spawn and join the player's last location. The entity also contains the player's entire record, experiences, and records. You can configure the assets' properties, equipment and experiences, and the behavior of the clone that will die the next time the player logs in, in the config.yml file. The entity reappears after the player rejoins."
https://www.spigotmc.org/resources/offlineplayers-never-let-players-disappear.104985/
