Do field enchantments, such as cards that say "opponent puts the top two cards of their library into their graveyard", stack with multiple iterations of it on my field? The specific example I'll use is what happened last night:
My friend had played two copies of Drowned Secrets and was basically milling me out for 4 cards every time he played a blue spell. I let it play out, but I would like to know what the legality of it is going forward. I'm aware of the Legendary card rule, but we're just getting into Magic, and we're learning the rules as we go along.