You conjure a quasi-real heavy chariot with four horselike creatures in a team to pull it. (The exact description can be customized as you wish.) The chariot has all the normal qualities of a heavy chariot. You or a person you designate while casting the spell must drive the chariot, which can carry up to six passengers (including the driver). The team and chariot make no sound and the team does not fight, although the driver can use the chariot like any normal chariot.

The chariot and team are essentially a single entity with an AC of 19 (–2 size, +6 natural armor, +5 Dex), and 10 hit points + 2 hit points per caster level (maximum 50). If the entity loses all its hit points, it disappears, possibly subjecting all aboard to a crash (treat as wrecked). The entity gains certain powers according to caster level:

8th Level: The mount can ride over sandy, muddy, or even swampy ground without difficulty or decrease in speed.

10th Level: The mount can use water walk at will (as the spell below, no action required to activate this ability). 

Water walk: The transmuted creatures can tread on any liquid as if it were firm ground. Mud, oil, snow, quicksand, running water, ice, and even lava can be traversed easily, since the subjects' feet hover an inch or two above the surface. Creatures crossing molten lava still take damage from the heat because they are near it. The subjects can walk, run, charge, or otherwise move across the surface as if it were normal ground.

If the spell is cast underwater (or while the subjects are partially or wholly submerged in whatever liquid they are in), the subjects are borne toward the surface at 60 feet per round until they can stand on it.

12th Level: The mount can use air walk at will (as the spell below, no action required to activate this ability) for up to 1 round at a time, after which it falls to the ground.

Air walk: The subject can tread on air as if walking on solid ground. Moving upward is similar to walking up a hill. The maximum upward or downward angle possible is 45 degrees, at a rate equal to half the air walker's normal speed.

A strong wind (21+ miles per hour) can push the subject along or hold it back. At the end of a creature's turn each round, the wind blows the air walker 5 feet for each 5 miles per hour of wind speed. The creature may be subject to additional penalties in exceptionally strong or turbulent winds, such as loss of control over movement or physical damage from being buffeted about.

Should the spell duration expire while the subject is still aloft, the magic fails slowly. The subject floats downward 60 feet per round for 1d6 rounds. If it reaches the ground in that amount of time, it lands safely. If not, it falls the rest of the distance, taking 1d6 points of damage per 10 feet of fall. Since dispelling a spell effectively ends it, the subject also descends in this way if the air walk spell is dispelled, but not if it is negated by an antimagic field.

14th Level: The mount can fly at its speed with a bonus on Fly skill checks equal to your caster level.