For almost as long as greedy manabases have existed, there have been cards that punish players for their hubris in using them — Blood Moon is one of the classics. It renders any nonbasic land, no matter how humble or how grand, into a (hopefully!) useless Mountain, leaving your opponent’s grip full of tricks dead in hand.
Blood Moon removes all abilities from a land (other than the ability to tap for Red mana that being a mountain gives), and removes all land subtypes by overwriting them with Mountain. What it does NOT do is mess with supertypes or actual card types. For example, your Highland Weald will only tap for R with the Moon out, but it’s still a Snow permanent. A legendary land such as Minamo, School at Water’s Edge will only tap for red mana, but it’ll still be Legendary. And, relevant to the current tip of the day, a Darksteel Citadel that’s gone Mountainous on you will still be an artifact, so it’ll still count for Affinity and Cranial Plating, and it’s still a legal target for spells such as Wear // Tear.
Now, why would you target a Citadel with Shatter? Because becoming a basic land type removes all printed abilities! Your Citadel is still an artifact, but it’s not indestructible anymore. Sad times ahead!
Today’s Rules Tip written by Trevor Nuñez