The field status Total Darkness has various effects.

Activation Means

The move Darkest Night.

Removal Means

Activating Harsh or Extremely Harsh Sunlight.

Activating Electric or Psychic Terrain.

Effects

Pokemon with the Chlorophyll ability have their Speed and Special Attack lowered by 30%.

Pokemon with the Infiltrator ability have their Speed and Attack boosted by 30%.

Dark type moves get a boost of 50%

Light based moves (Moonlight, Aura Sphere, Moonblast) have their power and effects reduced by 50%.

The weather condition of Harsh Sunlight will be removed, other weather conditions are unaffected.

Electric and Psychic Terrain are removed, Grassy and Misty Terrain are unaffected.

Supresses any Aura based attacks, abilites, or conditions.