Rule 702.108a

Dash represents three abilities: two static abilities that function while the card with dash is on the stack, one of which may create a delayed triggered ability, and a static ability that functions while the object with dash is on the battlefield. “Dash [cost]” means “You may cast this card by paying [cost] rather than its mana cost,” “If this spell’s dash cost was paid, return the permanent this spell becomes to its owner’s hand at the beginning of the next end step,” and “As long as this permanent’s dash cost was paid, it has haste.” Paying a card’s dash cost follows the rules for paying alternative costs in rules 601.2b and 601.2f–h.

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