Gavein

Gavein is a post X-Day Hyper-Zoanoid that only appears in the Guyver manga. This creature's body is covered with special oxygenation "fins" that resemble bracket fungus; these fins serve to generate electricity within Gavein's body through a hydro-dynamic chemical reaction. After these organic capacitors have generated enough energy, Gavein can then expel the electricity as blasts of lightning from its horn.