Antonio Brown was NOT making friends at the Buccaneers' joint practice with Tennessee on Thursday ... throwing punches and ripping a Titans player's helmet off in a wild brawl!!
Here's how it went down -- the 33-year-old Super Bowl champ was going up against 2nd-year cornerback Chris Jackson during some one-on-one drills ... when things got out of hand QUICK.
No word on what exactly sparked the altercation, but it had to have been serious.
Check out the pics .