Ex-NBA player Jerome Williams -- aka the Junk Yard Dog -- says he was offered $25 MILLION to start a rival 3-on-3 basketball league last year ... while he was still playing for the BIG 3 league.
But the craziest part ... Williams claims the people behind the offer were the same Qatari investors who already owned a piece of the BIG 3.
Of course, the BIG3 is suing the Qataris for more than $1 BILLION -- claiming they never made good on their $5 million investment ... and then threatened a league owner when asked for the money.