Mark Ruffalo -- who starred opposite Chadwick in the 'Avengers' movies -- posted a couple of touching photos of two little boys holding their own versions of wakes for Black Panther with their toys, placing the Marvel figurines in a circle around a laid out T'Challa.

He writes, "This is his power and impact on the next generation. #ChadwickForever." Mark's right here -- other kids were doing this as well in other parts of the country, including one boy named Kian ... who created a casket for his Black Panther action figure.

A guy named King Westbrook posted a photo of his son holding his own memorial outside their garage, with Kian throwing up a Wakanda Forever X-sign across his chest.

The proud papa says of his child, "Kian wanted to thank everyone from the bottom of his heart for all the loving and kind words given to him for this post." King goes on to add, "When he found out about Chadwicks passing, he was heart broken. But he knows death is a part for being human, and wanted to cope with losing his hero this way."