Mike Tyson might've forgotten who he was talking to during an interview with a young journalist ... giving a pretty blunt take on how he'd like to be remembered -- matter-of-factly saying nothing matters once we're all six feet under.
The hilarious interaction happened during a convo with a 13-year-old reporter named Jazzy ... who asked a very good question -- what is the legacy he wants to leave behind when he hangs the gloves up for good?
Iron Mike didn't mince his words .