Before going to sleep tonight, here it is, finally this is an Nake Wreckin's handheld sentient weapon,
RFG-X9000 "All-Terrain Multi-purpose Advanced Cosmic-powered" (A.M.A.C.) Gun. This is an original weapon belongs to Nake, and an bigger copied (black colored on below) version of it used by an mech, Deeron (https://www.furaffinity.net/view/40662619)

Enjoy folks ;) .

This also applies to Nake Wreckin ref for what this weapon finally looks like (I been waiting for this):
https://www.furaffinity.net/view/39882741/

Art commission drawn by  Kernkraftwerks

There 2 other versions of this art too:
Original colored: https://www.furaffinity.net/view/42401431/
Black colored: https://www.furaffinity.net/view/42401448/

Nake (who was mentioned above), and A.M.A.C. belongs to me.