Chain of Vapor is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Return target nonland permanent to its owner's hand. Then that permanent's controller may sacrifice a land of their choice. If the player does, they may copy this spell and may choose a new target for that copy.

Complete guide

Chain of Vapor is a high-stakes utility spell that offers incredible efficiency for a single blue mana. While it provides immediate tempo by bouncing a nonland permanent, it introduces a dangerous political element that can lead to a chain reaction across the table.

What It Does

Chain of Vapor is a bounce spell that targets a nonland permanent and returns it to its owner's hand. Its unique twist is the 'chain' mechanic: the player whose permanent was bounced has the option to sacrifice a land to copy the spell and target something new. This process can repeat as long as a player is willing to pay the price of a land to keep the chain going.

Step-by-Step Resolution

When the spell resolves, first, the target nonland permanent is returned to its owner's hand. Second, the controller of that permanent decides whether to sacrifice a land. If they choose to sacrifice a land, they put a copy of Chain of Vapor onto the stack. They may choose a new target for this copy. Note that this copy is created during the resolution of the original spell, and the new copy will resolve separately afterward.

Common Mistakes

One common error is thinking that sacrificing a land is required; it is strictly optional. Additionally, players often forget that the copy is not 'cast,' so effects that trigger on casting a spell will not trigger for the copies. Finally, remember that you cannot target a land with Chain of Vapor, though you must sacrifice a land to continue the chain.

When to Play It

Chain of Vapor is best used when you need to remove a problematic permanent immediately for very little mana, such as a stax piece or an aggressive blocker. It is also a powerful tool in combo decks to bounce your own cheap artifacts (like Mana Vault) to generate mana, provided you are willing to sacrifice a land to keep your momentum.

Interaction examples

Responding to the Chain

Counterspell

If you cast Chain of Vapor and your opponent chooses to sacrifice a land to copy it, that copy is a new object on the stack. You can use Counterspell to target the copy just like a normal spell, preventing the chain from hitting one of your own permanents.

Protecting Your Assets

An Offer You Can't Refuse

If an opponent targets your key noncreature permanent with a copy of Chain of Vapor, you can respond with An Offer You Can't Refuse. This counters the copy and gives you two Treasure tokens, effectively ending the chain and gaining you resources.

Self-Bouncing for Value

You can cast Chain of Vapor targeting your own nonland permanent. After it returns to your hand, you may sacrifice a land to copy the spell and target another one of your own permanents. This is often used in high-level play to reset 'enters-the-battlefield' abilities or to generate mana from artifacts.

Guide written with AI from the official text and rulings. Official English text prevails.