Built and tested on 1.16, but should really work on most versions.

Permissions

For a player to use a creeper egg, they need creeperegglaunch.creepegg.launch. To not deplete their supply of eggs, you can give them creeperegglaunch.unlimited

Commands

CREEPEGG charged ignited radius:# health:# fuse:#
creeperegglaunch.creepegg
Creates the special spawn egg. Pass no args and it makes a generic one with no special effects.


CREEPEGGCFG velocity #
creeperegglaunch.admin.velocity
Sets the velocity multiplier for the snowball's vector. Leave 1 for standard snowball, or raise it as desired to make the snowball fly faster

CREEPEGGCFG loretitle #
creeperegglaunch.admin.loretitle
Sets the first line of the lore that will apply to the special egg.

CREEPEGGCFG reload
creeperegglaunch.admin.reload
Reloads the config from disk

Localization

I made it so language support other than English would not be difficult. Just edit the config file and you'll see the messages section has the messages that get sent when you use the commands. The localization section has entries for each argument of the main command so you can adjust what the arg names are, so you could change from /creepegg charged to like /creepegg cargada if you so wish. The lore part of localization is what will show in the egg's lore for the feature. Be aware though that if you change the lore settings after the plugin has been in use, eggs created with the old values will no longer function properly. Same with lore title. The plugin looks for the lore title to know it's a special egg, so if you change the title old eggs won't be detected.

In retrospect, I probably should have tried seeing if I could apply the settings to the spawned item with tags or the persistent data container. I'll do that for version 2