I put eviolite on my Carbink accidentally thinking it was an everstone to pass down it's nature when I was breeding it. After breeding it a bunch of times and realizing my error, I took it out, and my buddy wanted to battle me. Since Carbuncle (that's what I named it) was still in my team, I used it in the battle. I noticed that it wasn't taking nearly as much damage as it should have been... so I tried taking it off, and it took a lot of damage.

why would this be?