Chris Brown Wants to Box Soulja Boy

Chris Brown wants to go toe-to-toe with Soulja Boy in a boxing ring, and it's all over a photo of Karrueche Tran.

Soulja says the beef all started when he liked a pic of Chris' ex, Karrueche, in a bikini. He says Chris hit him up, and threatened to whoop his ass.

It all sounds like some high school crap, but Chris is actually doubling down now, and reaching out to Adrien Broner to set up a charity boxing match.

His rant is awesome because as pissed off as Chris is, his priority at the moment was hooking up ... but he was way more blunt about it.

For what it's worth -- Soulja's been liking KT's pics for a while now, but she told us ... it ain't happening. Feel better, Chris?