Entwine

Entwine is a keyword ability appearing on modal instants and sorceries; i.e., ones with the “Choose one —” clause.

As you cast a spell with entwine, if you pay the additional entwine cost, instead of choosing only one of the modes of the spell, you choose all of them. In all cases but one, this is two options, and hence the reminder uses “both”.

Spells with entwine were featured in the Mirrodin block.

From the Comprehensive Rules (November 8, 2024—Edge of Eternities)

• 702.42. Entwine
  • 702.42a Entwine is a static ability of modal spells (see rule 700.2) that functions while the spell is on the stack. “Entwine [cost]” means “You may choose all modes of this spell instead of just the number specified. If you do, you pay an additional [cost].” Using the entwine ability follows the rules for choosing modes and paying additional costs in rules 601.2b and 601.2f–h.
  • 702.42b If the entwine cost was paid, follow the text of each of the modes in the order written on the card when the spell resolves.
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• You decide whether you’re paying the entwine cost as you cast the spell.
• If you choose not to pay the entwine cost, you can choose only one mode. If you choose to pay the entwine cost, you choose both modes.
• If you pay the entwine cost, choose targets for both modes as you cast the spell. When the spell resolves, follow the instructions in the order they’re written.