Twinferno — ruling 1

If the spell that's copied is modal (that is, it says "Choose one —" or the like), the copy created by Twinferno's delayed triggered ability will have the same mode or modes. You can't choose different ones.

Twinferno — ruling 2

If the spell that's copied has damage divided as it was cast, the division can't be changed (although the targets receiving that damage still can). The same is true of spells that distribute counters.

Twinferno — ruling 3

You can't choose to pay any additional costs for the copy created by Twinferno's delayed triggered ability. However, effects based on any additional costs that were paid for the original spell are copied as though those same costs were paid for the copy too.

Twinferno — ruling 4

The copies that Twinferno's ability creates are created on the stack, so they're not "cast." Abilities that trigger when a player casts a spell won't trigger.

Twinferno : règles, fonctionnement et interactions (MTG)

Twinferno 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

Choose one — • When you cast your next instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy. • Target creature you control gains double strike until end of turn. (It deals both first-strike and regular combat damage.)

Complete guide

Twinferno is a versatile red instant that offers players a choice between explosive combat damage or magical redundancy. Whether you are looking to double your offensive pressure or replicate a powerful spell, this modal card provides high utility for just two mana.

Dual Modes of Twinferno

When you cast Twinferno, you must choose one of two modes. The first mode sets up a delayed triggered ability that waits for you to cast your next instant or sorcery spell during the current turn. The second mode is a straightforward combat buff that grants one of your creatures double strike until the end of the turn, allowing it to deal damage in two separate combat steps.

Copying Spells Step-by-Step

If you choose the first mode, Twinferno resolves and creates an invisible trigger. When you cast your next instant or sorcery, that trigger goes on the stack on top of your spell. As the trigger resolves, it creates a copy of the spell directly on the stack. You can then choose new targets for that copy. Remember, the copy is not 'cast,' so it won't trigger 'whenever you cast' abilities, and it will inherit all modes and divisions (like damage or counters) chosen for the original spell.

Timing and Tactical Usage

Because Twinferno is an instant, you can use the double strike mode during the declare blockers step to surprise an opponent. If you are using the copy mode, you must cast Twinferno before the spell you wish to copy. If you cast a spell and then try to respond to it with Twinferno, the 'next spell' trigger won't apply to the spell already on the stack.

Interaction examples

Doubling the Chaos

Chaos Warp

Cast Twinferno choosing the first mode. After it resolves, cast Chaos Warp targeting an opponent's creature. Twinferno's delayed ability triggers and creates a copy of Chaos Warp. You can choose a new target for the copy. This results in two permanents being shuffled away and two library reveals, all for the price of one Chaos Warp spell.

Free Spells and Copied Targets

Deflecting Swat

If you control your commander, you can cast Deflecting Swat for free after Twinferno has resolved. Twinferno will copy Deflecting Swat. Since Deflecting Swat allows you to change targets of a spell or ability, having two copies of this effect on the stack allows you to redirect two different abilities or spells, or even ensure a redirection happens even if the first attempt is countered.

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

How it works : Twinferno

Original English text — Wizards of the Coast / Scryfall

#1September 9, 2022· Wizards of the Coast
If the spell that's copied is modal (that is, it says "Choose one —" or the like), the copy created by Twinferno's delayed triggered ability will have the same mode or modes. You can't choose different ones.
No other card is named in this ruling.
#2September 9, 2022· Wizards of the Coast
If the spell that's copied has damage divided as it was cast, the division can't be changed (although the targets receiving that damage still can). The same is true of spells that distribute counters.
No other card is named in this ruling.
#3September 9, 2022· Wizards of the Coast
You can't choose to pay any additional costs for the copy created by Twinferno's delayed triggered ability. However, effects based on any additional costs that were paid for the original spell are copied as though those same costs were paid for the copy too.
No other card is named in this ruling.
#4September 9, 2022· Wizards of the Coast
The copies that Twinferno's ability creates are created on the stack, so they're not "cast." Abilities that trigger when a player casts a spell won't trigger.
No other card is named in this ruling.