The sea legs spell stops the effects of oncoming seasickness in its recipient. If unable to do so before, that person also gains the ability to balance and maneuver easily even on a violently heaving deck, just as the most experienced sailor can. The reversed version of this spell, land legs, causes the target of the spell to become unsteady, likely to fall at the simplest of tasks while onboard a ship.
This spell originally appeared in this form in Powers and Pantheons for the AD&D game from TSR. Its use here is for the purposes of providing context for the campaign only.