Baoh is an OVA that was released in 1989. I watched the OVA when I was six or seven, and have acquired the Chinese and Japanese version since then. There is a manga of this work, but unfortunately I had never watched it…so I can’t say much about it.
Now what had always stood out in my mind of this anime, other than the very short plot was the gore and many blood scenes in this anime. Definitely not something for small children to watch, but even with that warning, there is the story of two orphans, a teenager and a girl.
Ikuroo was traveling with his parents when an accident occurred and he was captured by an evil organization. The organizations implanted a parasite into his mind, thus turning Ikuroo into a biological weapon. Of course he escaped before and along the way he met up with Sumire, a girl with psychic powers.
The main course of this OVA is that the organization tries to capture them again, so that they can use their powers in order of conquering the world or to earn a profit.
The name of Baoh is what the parasite that Ikuroo is infected with. The bug is injected and swims thorough the bloodstream to graft onto the brain stem, at the neck. (Was thinking about this image as I remember a scene where the scientists were testing out the Baoh bug.)
Anyhow, whenever Ikuroo is in trouble or feels threatened he turns from a human into a blue thing that looks pretty cool. The ending is on an exaggerated note, but as Wikipedia mentions, the only thing that can make the Baoh bug dormant is salt water. (The ending is that Ikuroo rescues Sumire from the organization and that Sumire said she will wait for Ikuroo as he sleeps on the ocean floor.)
Now these pictures may be a bit similar, but first one is a picture of Baoh. Third is the contrast between the human and Baoh. Second picure I found is a fanart that reminds me of Ikuroo and Sumire’s relationship.