Equestria Girls

After failing to prevent Twilight Sparkle from winning as princess of the Fall Formal, Sunset Shimmer threatens Twilight with destroying the portal back to Equestria if she doesn't surrender her crown containing the Element of Magic. Twilight quickly refuses and calls her bluff, stating that she will never let someone like Sunset Shimmer use her Element of Magic to endanger the human world.

Example of:
Screw Your Ultimatum!