I've run into him before. From his channel:
"About NibiruTheBrownDwarf
** ATTENTION ALL YOU TUBE USERS: I DON'T RESPOND TO ANYONE COMMENTING ON MY POSTS ANYMORE!!! I DON'T EVEN BOTHER TO READ THEM TOO MANY GOVERNMENT SHILL ATTACKS.**"
He's in the 'can't tell if stupid or trolling' class of user. I've seen his hit-and-run style of inflammatory comment before.
Carry on thought: There is a substantial chance this user is one of the channels created by PlanetXshockingproof, after he self deleted that channel in a rage quit. He uses the same language, the same emphasis on calling anyone that disagrees 'shills', and the same infatuation with the drawing from the children's encyclopedia. The creation of NibiruTheBrownDwarf came right on the heels of the self deletion of PlanetXshockingproof. BackToConstitution, as noted by other users, may also be involved.