Mob Effect Registry

StartupEvents.registry('mob_effect', event => {
  event.create('custom_effect') // Create the effect under "kubejs:custom_effect"
    .color(0x000000) // Sets the color of the Effect's Particles.
    .beneficial() // Categorizes the Effect as Beneficial.
    .effectTick((entity, lvl) => { // This useful for reoccurring logic while the entity is under the effect.
      // Heal the entity once a second scaled by the effect's level, much like regeneration.
      if (entity.age % 20 != 0) return
      entity.heal(1 * lvl)
    })
    // modifyAttribute is useful to scale an entity's attributes only lasting while under the effect
    .modifyAttribute('minecraft:generic.attack_damage', // The attribute to scale
      'e0f4e796-3d3d-11ee-be56-0242ac183754',//Some random UUID which serves as the effect's unique instance
      1, // The amount to increase/decrease by
      "multiply_base" // The operation to perform
    )
})

onEvent('mob_effect.registry', event => {
  event.create('custom_effect') // Create the effect under "kubejs:custom_effect"
    .color(0x000000) // Sets the color of the Effect's Particles.
    .harmful() // Categorizes the Effect as Harmful.
    .effectTick((entity, lvl) => { // This useful for reoccurring logic while the entity is under the effect.
      // Heal the entity once a second scaled by the effect's level, much like regeneration.
      if (entity.age % 20 != 0) return
      entity.heal(1 * lvl)
    })
    // modifyAttribute is useful to scale an entity's attributes only lasting while under the effect
    .modifyAttribute('minecraft:generic.attack_damage', // The attribute to scale
      'e0f4e796-3d3d-11ee-be56-0242ac183754',//Some random UUID which serves as the effect's unique instance
      1, // The amount to increase/decrease by
      "multiply_base" // The operation to perform
    )
})