So it's kinda weird here, but I think that using the blood manipulation technique from the death paintings he consumed, Yuuji reattaches his foot that was sliced off
Like, it was on the ground. Then we see it in the air with a stream of blood connecting it to him
And then, in the next panel, it's attached again, and he's standing on it
its really cool that we discovered glass which is the material that doesnt have any chemical reactions with anything in the universe very useful for doing chemistry due to being able to put things in it to contain chemical reactions and never having it react with the things that are in it due to it being completely and entirely unreactive to every chemical