Conway's Game of Life within Conway's Game of Life.
The pattern that emulates a single life cell is called “unit life cell”. First discovered in 1996 by David Bell.
there are several different constructions of unit life cell. Others are:
The one in the video is the OCTA metapixel. It is the only one so far that also VISUALLY emulate Game of Life
Here's another vid:
the software used is “Golly”. See: Great Software for Cellular Automata.
see also: Notes on A New Kind of Science.