In video obtained by TMZ ... Joshua -- AKA “World of T-Shirts," who has a following of nearly 4 million -- can be seen screaming incoherently on the street before he repeatedly smashes his face into a wall.

What appears to be his pals grab him and try to make him stop before he really hurts himself ... as JB keeps yelling.

It's not clear what set Joshua off ... but in another video, he can be seen getting bear-hugged by a passerby who apparently initiated a citizen's arrest, as Joshua yells, "I can't breathe!"

There is another video in which JB is being talked to by police ... but it does not appear that he is under arrest ... which he confirmed in a video of his own, saying it was merely a citizen's arrest, cops gave him a talking to ... and the situation was over.

The videos sparked a heated debate on social media ... mostly a combination of worry for Joshua's mental state ... but also the responsibility influencers have with their behavior -- especially in another country!

But ... that's sorta Joshua's MO ... 'cause he's made a name for himself with his wild behavior and antics ... which included once literally licking the ground of a subway car.