A wereform is a condition of sapient humanoids causing them to transform into a beast form, usually during the full moon. It specifically refers to terrestrial, aggressive therianthropy. The forms are usually bipedal or of the same primary locomotion of the original creature, but the beast form itself ultimately dictates the resultant locomotion. It is usually a contracted condition, passed on through the bite of another wereperson, but some can be born with it as a power and some wereforms can be controlled at will.