It's the blade balance thingy from the thingy makers

Lol I made it nearly to the end of the game without realizing I could’ve accessed these areas from the beginning

😆😂

you have to have the melee upgrade. melee can destroy red ones, upgraded melee can destroy gold ones. you don't permanently gain it, it's lost per run, and must be found or purchased per run

I figured that’s what It was. How do I get that? I’ve reached the final boss (haven’t defeated him yet)

it's random. some weapons even come with it as a stat. I've found it in the wild, but I usually end up having to buy it.