Almost all living things in the Otherworld have a spirit form. The most obvious parallel are the dryads of classical mythology. However, while trees do have spirit forms that appear almost human and can move somewhat independently of their physical forms, this is not so for all Otherworld creatures. The smaller plants are known to have significantly less humanoid but mobile spirit forms. Those animals that have been identified and catalogued, such as the Unicorn, seem to have spirit forms that are co-dependent with their physical forms in a manner that needs further investigation. As with plants, smaller animals seem to be less humanoid in their spirit forms.
So far, study has not conclusively shown whether the simple, microscopic creatures, single cell organisms or fungi have spirit forms. There is much academic and theological debate on this matter.
“Second Sight” is a phrase used to describe the ability to see spirit forms.