Mana Breath

The Mana Breath spell, which constantly drains mana once activated, allows the caster to breathe underwater, the same way a blue potion would do. It allows to do longer tasks under water without the danger of drowning. This makes it downright useful, but the danger of running out of mana while underwater negates some of its usefulness; therefore, use it with caution.

Trivia

 * This is the only spell in Ultima IX that can be cast while being under water.