Water Ultima II

Like other Second level Ultima Spells, excluding the Air Ultima II, Second level Ultima Spells are not able to cast.

The Water Ultima II is an uncastable spell, and the most powerful water spell in RuneScape. Despite uncastable, it can be witnessed by fighting Gill in Ultima Destroyer form and Gerssick in any form. It is composed of a water missile which is two times larger than Water Surge and spawns five surge missiles, then followed by Ice Age.

Ice Age
Like other Ultima II Spells, the main missile will remain static until the surges exploded to the player. The main missile will act as a water spout. After surges ran out, the missile will also explode and a dry ice missile will hit the ground and will turn the ground into chilling ice, making the player crawl and lose energy and reduce stats. It also hurts you by 10 constantly.

The subspell lasts for 25 seconds before the ice thaws out and transforms into Ice Barrage (unfailable).