For some cards, surge represents only an alternative cost, a discount that applies if you or a teammate has cast another spell this turn. Other cards, like Reckless Bushwhacker, have additional abilities or effects if you paid the surge cost to cast the spell.
Casting a spell for its surge cost doesn't change its mana cost or its mana value.
The other spell that you or a teammate cast can be one that's resolved, one that was countered, or (for instants with surge) one that's still on the stack.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Ryan Pancoast
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If an instant or sorcery spell cast for its surge cost is copied, the copy is also considered to have had its surge cost paid.
