How would the world have reacted to a Christina Aguilera and holographic Whitney Houston duet on The Voice finale? Well, we'll never know because Whitney's estate scrapped the whole stunt, for obvious reasons. Instead, last night The Voice swapped one diva for another (albeit one far less legendary than Whitney) and gave us two dangerous women locked in a vocal duel. Watch as Ariana Grande and Aguilera go vocal run for vocal run in a marathon cover of Grande's "Dangerous Woman" with no true finish line. Somewhere in outer space, their competitive riffing is still going strong. We can only applaud Ariana for resisting the temptation to bust out her famous Xtina impression and throw Christina off her game. In fact, how did no one think to have the two impersonate each other for this entire diva-off? Amateurs.