President Trump's not the only one threatening the U.S. Post Office these days -- meet this maniac, who screamed, yelled and busted out some martial arts ... until a Good Samaritan got involved.
Check out this wild video of the guy losing it on a fellow customer -- a younger woman -- inside a Northern California Post Office. Both of them were at the counter when an argument erupted, and screamed his face off at her.
She stood her ground, which seemed to piss him off even more -- and that's when he flew into a half-assed karate stance of some sort. That drew laughs from some bystanders, but another stepped in with some words of wisdom.
A man who jumped into the fray told the Chuck Norris wannabe to scram and reminded him he's violating federal law by threatening people in a U.S. Postal Office. That seemed to finally get through to him, and he went outside.
Never a dull moment for the USPS, which Trump has been bashing nonstop -- claiming it's gonna ruin the election by screwing up the handling of mail-in ballots.
As for the threatening jerk in the Post Office ... we doubt he knows karate, but he seems to know kar-azy. Shoutout to James Brown!!!