Dagannoth mother (Horror from the Deep)

The Dagannoth Mother is fought at the end of the quest Horror from the Deep. She constantly cycles through different colours to blatantly show her weaknesses.

The Colours of the Rainbow
White: She is currently weak to Air Spells (Air Strike, Air Bolt, Air Blast, and Air Wave.)

Blue: She is currently weak to Water Spells (Water Strike, Water Bolt, Water Blast, and Water Wave.)

Brown: She is currently weak to Earth Spells (Earth Strike, Earth Bolt, Earth Blast, and Earth Wave.)

Red: She is currently weak to Fire Spells (Fire Strike, Fire Bolt, Fire Blast, and Fire Wave.)

Orange: She is currently weak to Melee.

Green: She is currently weak to Range or Special Attacks.

It is advised to hide behind stalagmites when the Dagannoth Mother turns a colour players aren't prepared to fight. Protect from Melee is advised as her Ranged attack is weak. She can hit up to 16 with Melee.