Here's the deal ... a streamer -- who goes by the name Dumbdumbjeez on the platform -- posted a video of sitting across from a woman named Mabel, who he says is homeless.

Dumbdumbjeez opens the bill, sees the $76 price tag and tells his dinner companion he needs to go get his wallet out of his car ... before walking out the front and taking off for a waiting car down the street.

The clip's gone viral, and Kick's cofounder Bijan Tehrani says he didn't find this "prank" that funny ... taking to social media to let people know that Dumbdumbjeez was trying to win a $50K contest -- and, said he'd receive a ban from the company instead.

Tehrani says the company is happy to give Mabel $50K dollars if anyone can connect the two parties.

BT may want to hold off before writing any checks though ... 'cause Dumbdumbjeez says he briefed this woman on the whole situation before running out the door.

He says he tried to rig the contest -- which asks people to take a stranger on a date -- saying he'd already given Mabel the cash ... so, no one was actually harmed in the making of the clip.