Inlaid Armor?

So I had a friend that is new to the game ask me about the "Inlaid Armor" corrupted mod, yet I don't recall ever seeing it. Is this still a thing? If so, is it still obtainable, or is it something incredibly fucking stupid like waiting for the acolytes to return once a goddamn year, while scratching your butthole with your left hand, pinching your nose with your right hand, and whispering sweet nothings to the universe?