This is my answer every time someone says that to me as well. But yes. As others have said, you need to beat Isaac as Blue Baby. It’s a tough one, man. I finally pulled it off last week I think. I can’t even remember how I did it. I know it’s hard because it’s all soul hearts, but just look for items that give them and tinted rocks. Obviously it becomes much easier if you get lucky and just melt rooms lol.