Dok Gillgivva was made mostly from an Assault on Black Reach Nob. The Klaw and Bionik arm are from the plastic Nob box. I carved down a Slugga for the left bionik arm. To both arms I added syringes made from thick plasticard rods, paperclips, and Space Marine Meltabombs with the middle square bits carved out. The Head light was custom sculpted. I cut the goldfish out of plasticard, and added plasticard gills and used a pin vise for the eye.
Gillgivva was painted like my other orks, with dipping. I then added some dynamic lighting effeccts from the green liquid on his left arm to make it look like it was glowing.
For the 'Ard Boyz, I used wooden spheres for the heads and custom sculpted the victorian grilles. The tubing is Lego Pneumatic tubing, and the air tanks are Imperial Guard Flamer tanks.
Ol' Dok Gillgivva earned his name when he realized that the skin of a slime squig, carefully applied to an incision on a Boy's neck, could filter "da good stuff" out of water, essentially giving an Ork gills, allowing him to breathe underwater.
His first experiments did not breathe water well, so to compensate, he used multiple slits, all around the neck. This improved water breathing efficiency, but made the Ork unable to breathe regular air. To compensate for this, he sends them to Manik Upzindownz, the Mad Mek, who sells them an expensive apparatus designed to let them carry around a water supply. Designed by Gillgivva himself, this system incorporates water containers coated with that same slime squig skin, allowing the water to be re-oxygenated and sent to a helmet where the Ork can breathe it in.
To protect their new weakness, most of Gillgivva's "patients" become Ard Boyz, armoring themselves and their water supplies. Though they can breathe underwater, this prevents them from being amphibious as the armored packs are heavy, and without them they could not leave the water. These Ard Boyz tend to hang around Gillgivva, because after all, gills need maintenance and he has not found a way to give you gills twice.
Gillgivva was the Dok who put Poindexta Smartyskull's brain(s) in, and Smartyskull keeps him around, protecting him from his victims in exchange for a promise never to give Smartyskull gills.