This is more of a card question than a rules question and I do apologize, but I couldn't clearly find a forum for card questions.
Any ways my question is about "Revolutionary Rebuff" a Blue instant from Kaladesh which reads "Counter target non artifact spell unless its controller pays 2 mana." Can this card be used to counter a Monster/Creature from summoning and send it directly to the Graveyard before it can do anything??? Like "Enraged Giant" a Red Creature from Aether Revolt. To me "Counter target non artifact spell unless its controller pays 2 mana." sounds like a card to counter a sorcery spell or creature effect, not counter a creature summoning. Any Clarification on this would be most appreciated.
A spell is any nonland card that has been cast and is on the stack. Revolutionary Rebuff can target any creature, enchantment, instant, sorcery, or planeswalker on the stack and counter it unless its controller pays 2. If a card can counter abilities, it would be worded like Disallow.
A "nonartifact spell" means a spell without the type "Artifact" in its type line (C.R. 109.2b). Therefore, it includes most creature spells, but not artifact creature spells, for example (C.R. 205.2b). (Note that creatures [not: monsters] exist only on the battlefield; a creature card that was cast [not: summoned] and is on the stack is called a creature spell [C.R. 109.2, 109.2b, 112.1].)
EDIT (Apr. 9): A "nonartifact spell" doesn't include abilities of creatures; such abilities are not called "creature effects" (compare C.R. 112.1, spells, with C.R. 113.1, abilities, and C.R. 609.1, effects).
EDIT (Feb. 5, 2020): Edited, including because some rules were renumbered with Core Set 2020.
Any ways my question is about "Revolutionary Rebuff" a Blue instant from Kaladesh which reads "Counter target non artifact spell unless its controller pays 2 mana." Can this card be used to counter a Monster/Creature from summoning and send it directly to the Graveyard before it can do anything??? Like "Enraged Giant" a Red Creature from Aether Revolt. To me "Counter target non artifact spell unless its controller pays 2 mana." sounds like a card to counter a sorcery spell or creature effect, not counter a creature summoning. Any Clarification on this would be most appreciated.
Thank You
EDIT (Apr. 9): A "nonartifact spell" doesn't include abilities of creatures; such abilities are not called "creature effects" (compare C.R. 112.1, spells, with C.R. 113.1, abilities, and C.R. 609.1, effects).
EDIT (Feb. 5, 2020): Edited, including because some rules were renumbered with Core Set 2020.