Suge Knight -- 2Pac Needs Star on Walk of Fame ... OR ELSE!!!

Suge Knight says he's on a mission to get Tupac Shakur enshrined on the Hollywood Walk of Fame ... and tells us, if his demands aren't met -- there will be SERIOUS consequences.

Knight was getting his truck washed in Malibu yesterday when he issued his threat -- "If they don't hurry and put Tupac on the Walk of Fame, all the Tupac fans and all the homies are gonna start going down there and just scratching all the other names off."

Knight says no celebs will be off-limits when his boys start destroying the stars -- including Elvis.

He even took a shot at Diddy while making his argument -- ya gotta hear it.

There's more ... Suge also blasted his Interscope Records honcho Jimmy Iovine -- comparing the music mogul to a Ku Klux Klansman (even though Jimmy is now business partners with Dr. Dre).