Its Cross's Mob Effects

Mob Effects allows players and modpack creators to apply configurable status effects to mobs through an easy-to-edit config file. Customize creatures by giving them unique abilities, buffs, or weaknesses to create harder challenges, special encounters, or completely new gameplay experiences.

By default, the mod generates a configuration file containing available mobs, including vanilla and modded entities, organized by category. Each mob can have multiple configurable effects such as regeneration, resistance, fire resistance, water breathing, slow falling, weakness, and strength (any effect). Effect levels, durations, and particles, can all be adjusted to fit your preferences.

This mod is ideal for players who want more control over their world's difficulty and mob behavior without replacing existing mobs or requiring custom entities. Create tougher enemies for survival challenges, give specific creatures unique abilities, or design custom modpack experiences where every encounter feels different.

Features:

• Apply configurable status effects to vanilla and modded mobs.
• Supports multiple effects per mob.
• Automatically generates a config file with available entities.
• Organizes vanilla and modded mobs separately for easier editing.
• Configure effect type, amplifier level, duration, particles, and icons.
• Supports infinite-duration effects.
• Works with custom modpack setups and modded creatures.
• Allows complete control over how mobs are enhanced without changing their base behavior.