Reckless Bushwhacker
Creature — Goblin Warrior Ally
Surge 
(You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Haste
When this creature enters, if its surge cost was paid, other creatures you control get +1/+0 and gain haste until end of turn.
Kieran Yanner
The List (PLST)
• #OGW-116Rulings
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.
(wotc • 2016-01-22)
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.
(wotc • 2016-01-22)
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.
(wotc • 2016-01-22)
Casting a spell for its surge cost doesn't change its mana cost or its mana value.
(wotc • 2016-01-22)
Rulings
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.
(wotc • 2016-01-22)
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.
(wotc • 2016-01-22)
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.
(wotc • 2016-01-22)
Casting a spell for its surge cost doesn't change its mana cost or its mana value.
(wotc • 2016-01-22)