This is kind of stupid

[Kiki-Jiki, Mirror Breaker]

Ok
I summon vorinclex. My opponent act of treasons it. I cancel, but he uses fiery fall, sacs it, and gets three mana. Can he do that?

[cltrn81]

If he legally takes control of your creature, he can sac it.  I use {act of treason} and {fling} in a deck I have.  I then say thank you for your creature, he attacks you, then I fling him in yo face, and I sum it all up with a closing argument of BOOYA!!!

[Kiki-Jiki, Mirror Breaker]

Ok

[BlackJester]

Ok
I summon vorinclex. My opponent act of treasons it. I cancel, but he uses fiery fall, sacs it, and gets three mana. Can he do that?

Let's get some links here:
{Vorinclex, Voice of Hunger}
{Act of Treason}
{Cancel}
{Fiery Fall}

If you Cancel his Act of Treason, he won't have control of Vorinclex to sac it for anything. The Act is still waiting to resolve.

[BlackJester]

Also, I think you meant {Infernal Plunge} instead of {Fiery Fall} (Infernal=Fiery, Fall=Plunge ðŸ˜,), and since the plunge is a Sorcery, your friend couldn't have cast it in response to anything. He needs a slap in the face with the Rule Book. 😱

[Kiki-Jiki, Mirror Breaker]

Ok cool! I have a rule book I can spare......

[Chaosquirrel]

But if he {cancel}ed {act of treason} his opponent never gained control of his creature to sac it. Or did I read the scenerio wrong?

[cltrn81]

Right...he never gained control to sac.  That is why I said "if he legally gained" control then he could sac.  I thought the question pertained to sacing someone's creature if you gained control temporarily.