Dangerous life form once home to Narl Gatu .
These semi sentinent "Nul Dragons" grow up to 12 meters and have a natural ability to manipulate gravity (enabling them to fly)
The species increased abilities was a gift of the Seenians to the Nul about a Million years ago. The Nul keep several thousand specimen alive and have returned a few hundred to Narl Gatu
Fighting and surviving a Gravi Defier is considered highest honors.
Har-Hi was the first non Nul to slay a Gravi Defier (beating Erica to it by seven minutes)
These beasts use gravitation control as main form of attack but also have jaws able to crack a Nul skull and strong and fast tentacles.
The skull of a Gravi Defier hung in the Pirate Den of the USS Tigershark and is now in the recreation of the Pirates Den at the Union Museum and the Tigershark exhibit .