Howdy! My friend decided to Supplant Form my Stormtide Leviathan. I was on my way out and decided to mess with him and cast Gift of Tusks on the Stormtide Leviathan, while Supplant Form was on the stack.
So, question: Does his copied 3/3 Elephant named Stormtide Leviathan turn back into a giant fish creature at the end of his turn, or does it stay a 3/3 Green Elephant forever?
Gift of Tusks doesn't do anything here. When creating a copy of an object, you copy what is printed on the card and only account for other copy effects. Since there are no other copy effects here, Supplant Form is going to create a copy of Stormtide Leviathan whether you cast Gift of Tusks or not. Here is the rule:
706.2. When copying an object, the copy acquires the copiable values of the original object’s characteristics and, for an object on the stack, choices made when casting or activating it (mode, targets, the value of X, whether it was kicked, how it will affect multiple targets, and so on). The “copiable values” are the values derived from the text printed on the object (that text being name, mana cost, color indicator, card type, subtype, supertype, rules text, power, toughness, and/or loyalty), as modified by other copy effects, by its face-down status, and by “as . . . enters the battlefield” and “as . . . is turned face up” abilities that set power and toughness (and may also set additional characteristics). Other effects (including type-changing and text-changing effects), status, and counters are not copied.
So, question: Does his copied 3/3 Elephant named Stormtide Leviathan turn back into a giant fish creature at the end of his turn, or does it stay a 3/3 Green Elephant forever?
Supplant Form
Stormtide Leviathan
Gift of Tusks
Gift of Tusks doesn't do anything here. When creating a copy of an object, you copy what is printed on the card and only account for other copy effects. Since there are no other copy effects here, Supplant Form is going to create a copy of Stormtide Leviathan whether you cast Gift of Tusks or not. Here is the rule: