From Melvor Idle
This page is up to date (v1.3).
Archaic Magick ID: melvorTotH:Tsunami
Magic Level 108
100 Twin Sea Dragon Serpent Kills
Spell Damage: 190
You conjure immense waves that crash into the enemy, dealing damage equal to 100% of your max hit 3 times over 0.6s. On a hit, gives the enemy +20% Attack Interval for 3 of the enemy's turns. Avoidable.
25 Water Rune, 5 Archaic Rune, 5 Calamity Rune

Tsunami is an Archaic spell that is unlocked by killing 100 Twin Sea Dragon Serpents. This spell requires a Magic level of 108 to cast and inflicts damage equal to 100% of your max hit 3 times. There is a 0.3 second delay between each of the 3 attacks for a total duration of 0.6 seconds. Each hit increases the enemy's attack interval by 20% for 3 of the enemy's turns. This attack is avoidable.

As with all Archaic Magicks, damage modifiers from equipment, prayer, and potions will apply. Curses and damage-modifying Auroras can also be used, though special attacks will not work.