Airy water

The airy water spell turns normal liquid, such as water or water-based solutions, into a less dense, breathable substance. Thus, if the wizard wanted to enter an underwater place, he would step into the water, cast the spell, and sink downward in a globe of bubbling water. He and any companions in the spell's area of effect can move freely and breathe just as if the bubbling water were air. The globe is centered on and moves with the caster. No water-breathers can breathe in an area affected by this spell. The spell does not filter or remove solid particles of matter.

Note: This version of airy water originally appeared in the 2nd Edition Player's Handbook for Advanced Dungeons & Dragons from TSR. Its use here is for the purposes of providing context for the campaign only.