From The Wajas Wiki

Unihorn is a type of Custom Mutation. You can get this mutation the following ways: Randomly from a Mutation Pear, Applying a Unihorn DNA to your waja, or by making a Custom with it. When creating a custom with Unihorn, you cannot change its color. It will always come out white, or brown on Forest only (to resemble wood).

Mutation Appearance

UnihornAerial.png UnihornAfrican.png {{{arctic}}} UnihornBane.png {{{breedless}}} UnihornCorsie.png UnihornDivine.png UnihornEarth.png UnihornEgyptian.png UnihornFire.png UnihornForest.png UnihornImp.png UnihornNormal.png UnihornPlushie.png UnihornSpitz.png UnihornTempest.png UnihornWater.png