Lodestone Needle // Guidestone Compass

Nov 10, 2023 · The back faces of some cards with craft refer to cards "used to craft" it. This refers to the cards exiled as part of the cost of the craft ability of the front face. Those cards are considered to be "used to craft" that permanent as long as they remain exiled and the permanent remains on the battlefield, even if the permanent's controller changes or some of its characteristics change (because of a copy effect, for example.)

Nov 10, 2023 · If no card is revealed, most likely because that player's library is empty, the exploring creature receives a +1/+1 counter.

Nov 10, 2023 · If the materials required include multiple objects, you may exile some of them from among permanents you control and the rest from among cards in your graveyard. You don't have to choose all permanents or all cards from your graveyard.

Nov 10, 2023 · If an ability instructs a creature to explore, its controller reveals the top card of their library. If it's a land card, they'll put it into their hand. Otherwise, they'll put a +1/+1 counter on that creature, then choose to either leave that card on top of their library or put it into their graveyard.

Nov 10, 2023 · Once an ability that causes a creature to explore begins to resolve, no player may take any other actions until it's done. Notably, opponents can't try to remove the exploring creature after you reveal a nonland card but before it receives a counter.

Lodestone Needle's enters-the-battlefield ability can target an artifact or creature that's already tapped. If so, you'll just put two stun counters on that artifact or creature.