An Ohmu abandons it's shell and skin every so often, they bleed blue blood, and they have 14 eyes. They release spores that, when landed on the ground, grow into miasma-producing plants.
One scene of the manga has (the main character) Nausicaa, her dress dyed blue with Ohmu blood, being held into the air by the feelers of the Ohmu. At first look she looks like a young lost soul, standing in a field of golden grass.
*Note, the manga version differs greatly from the anime version. Remember that the anime version was made when only the first 200 or so pages came out, while there are about 1000 pages of the manga total*
