Monster Growth is a very customizable system that will alter common monster spawning. It alters monster's spawn locations and makes them stronger using "no damage ticks".

By default, instead of spawning a new monster, the plugin will strengthen an existing monster until a set limit. A new monster will spawn only after all existing monsters are 'buffed'. Buff in this case means the monster is more resistant by increasing the "no damage ticks" or "invincibility frames". This is the time a mob is invincible after being damaged. This way it can stack with other effects like health, armor or potion effects.

Aside from this, monsters have a higher chance of spawning near other monsters and spawn as the same type as the existing monster. What this will result in is that monsters are a bit rarer, but are found in larger groups. They are stronger, and groups will be of mostly one type.

To compensate this, the stronger the monster, the higher the reward will be for killing them. Reward being extra drops or extra exp. All of this is customizable.

This section will go through all the values that can be used to configure the plugin. Before going into the details, here is what the default config looks like:

Code (YAML):

# This is the configuration file for MonsterGrowth.
# 20 ticks is about one second.
#
# Note that this plugin only affects naturally spawning mobs (not spawners, summons, special encounters, etc).

Tick increment trigger in seconds (0 or below for spawn event trigger) : 0.0
Tick increment amount : 30
Tick limit for new mob : 80
Tick exp multiplier : 1.5
Tick item drop multiplier : 1.5
New mob location chance : 30.0
Multiply new location chance for each player : true
Grow same mob type chance : 90.0
Mob types that can be affected by the plugin ('null' for all monsters) :
- ZOMBIE
- SKELETON
- CREEPER
- SPIDER
- CAVE_SPIDER
- DROWNED
- ENDERMAN
- ENDERMITE
- EVOKER
- GUARDIAN
- HUSK
- ILLUSIONER
- PHANTOM
- STRAY
- VINDICATOR
- ZOMBIE_VILLAGER

Most of the settings are related to monsters spawning and the combination of settings result in certain behaviour.

The first three settings directly tie together. The first setting Tick increment trigger in seconds is the spawn trigger for monsters. 0.0 will use the default Minecraft spawn event as a trigger. Anything else changes the trigger into a timer. Each time this trigger goes off, a monster's "no damage ticks" are raised by Tick increment amount. If all involved monsters have their "no damage ticks" up to Tick limit for new mob or higher, a new monster will spawn.

As an example, let's say the following values are used:

Code (YAML):

Tick increment trigger in seconds (0 or below for spawn event trigger) : 10.0
Tick increment amount : 15
Tick limit for new mob : 40

A monster starts with a "no damage ticks" value of 20 (which is equal to 1 second). After the first 10 seconds, a monster spawns. The next 20 seconds will be used to add 30 (2 * 15) "no damage ticks" to this monster. The monster will have 50 "no damage ticks" at this point and is above the set limit, causing the next 10 seconds to spawn the next monster, and the cycle repeats.

With each trigger, aside from the no damage tick count being increase, the amount of exp and items dropped when the enemy is killed is also multiplied by Tick exp multiplier and Tick item drop multiplier. Note that de default 1.5 is quite high, since it is applied with each increase of ticks, so two times in the example, resulting in 3x items and 3x exp.

Monsters will spawn at new locations less often. The next two settings: New mob location chance and Multiply new location chance for each player regard the monster spawn location. The default 30.0 means there is only 30% chance a newly spawned monsters gets a unique location. The other 70% of the time it will be spawned near an existing monster. The setting to multiply this with each player means the chance is doubled with each extra online player, meaning 60% when there are two players online (I'm not exacly sure about this one, since it has been 4 years).

The last two settings regard the types of monsters. Grow same mob type chance is the chance for a newly spawned monster to be of the same type as an existing monster at that location.
And lastly, Mob types that can be affected by the plugin determines the types of mobs that are involved in this system. This is a list of EntityTypes. All EntityTypes can be found on the Spigot API. Replacing this list with the value 'null' (mind the quotes) will enable the system for all mobs that are considered monster by the API (see "All Known Subinterfaces").
There are currently no known bugs.

This plugin should be compatible with versions 1.13 and up.
This plugin was developed mostly in 2018.