This sylvan creature can change at will between two forms: an intelligent horse and a powerful centaur.
As a horse, a chevall may be any color (though a given individual does not change shades). It is typically as large as a light war horse. In centaur form, it has the upper torso and arms of a human being and the lower body of a horse. This form tends to be somewhat smaller than most centaurs, on average, and its ears, unlike those of a standard centaur, are pointed and elfin.
In either form, a chevall can talk to and understand horses, using sounds which, to human ears, are nothing more than neighs and whinnies. Using this whinnying language, a chevall can command any horse, wild or domesticated, to do its bidding. A paladins warhorse, and other unusual mounts with average Intelligence or higher, are immune.
In centaur form, a chevall can speak Common, the language of centaurs, and woodland sylvan tongue.