This is an original machine I made using the GQ Rick Dom.
In the official story, there is the "MS-09K-1/MS-09K-2 Dom Cannon," which is a Dom Tropical Test Type with a cannon attached to its back, so I made this original machine based on the fantasy that it might also exist in the Sieg-Axe world line.
Actually, I really didn't like the third leg on the back of the GQ Rick Dom, so I removed it, and since that alone left the back looking a bit lonely, I decided to give it a cannon attached to its back.
It seems that many people don't like the legs on the back of the GQ Rick Dom, but if you simply remove them, the butt is completely exposed because there is no rear skirt.

Dom Cannon (GQ) | GPO144's Gunpla works