Controversial TikTok Star Joshua Block just had a major breakdown in Japan … and his erratic behavior got so bad, police had to get involved.

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.

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.