Firstly, what would you call the name of the this type of effect? Is it simply considered blurring?
And secondly, how would you go about achieving this? No idea were I would start. It looks like they are just lerping to increase the size of all pixels and lerping back to normal. Would using shaders be easiest?
Anyway, this is called de-res, or de-resolution. There are a few ways to do it. It is not a blur.
You could do it with a rendertexture or grab to texture… once you’ve got the screen stored in a texture, you have a couple of options… you could do a custom shader which then outputs that texture (to a quad/cube covering the screen) but which modifies the texture coordinates on the fly so that multiple pixels sample the same source pixel, based on a scale factor. Another way is to instead draw the texture at a smaller size (either to the backbuffer and regrab it, or to a render texture)… and then re-draw that smaller texture covering the whole screen.
The easiest way I think is with the shader - less steps.