One of Kung Lao's fatalities where he beats his enemy to death, with a bunny rabbit.
Even funnier, he has one where hands the bunny to the enemy, only for the bunny to maul them instead.
Cage provides a few as well. Like interrupting your fatality on Goro or his new Ball-Breaker fatality.
What about beating Shao Kahn to death with Kintaro's freaking severed head? Its a viable tactic too, considering it does some good damage against him.
An unintentionally hilarious moment occurs right before you battle Baraka. Baraka toys with a monk he has impaled on his retractable spikes. When Baraka notices the Shaolin Monks arrive, he decides to do away with his captive and impales him through the head before tossing him over to Liu-Kang. Liu Kang's immediate reaction to all this...is approaching the monk's corpse and asking "Are you okay?". WOW.