These are what think the Secondary fatalities might have been like if MK:DA had them.

Drahmin: He raise his club up in the air and all the fly’s from his body start swarming around it. Then in a quick snaping motions he reaches his arm back and extends it outward send the fly’s, well flying at the opponent. The fly’s cover the opponent’s body head to toe flying around the body. You see blood and chunks of flesh flying off the body fast and in huge amounts. Eventually the fly’s return to Drahmin leaving the opponent being only a bloody skeleton with chunks of meat hanging from the bones. (I actually suggested this a while back.)

Reptile: Reptile turns invisible and then all we see is the opponent lifted from the ground with the body being in a limp state. It hangs there for a bit and the opponent coughs up some blood. Then the opponent’s stomach explodes sending organs, blood, and chunks of meat sailing outward leaving a gaping hole from the bottom of the rib cage all the way down to the pelvic bone. The body then falls to the ground and we see a blood puddle forming under the corpse.

Jax: Jax pulls out his machine gun and begins firing upon the opponent. They stumble backwards like usually only with chunks of flesh and meat flying off of them. They begin to deteriorate in form with holes all over their body until they just crumble in a pile of torn flesh and guts, leaving a trail of flesh, blood, and torn up guts.

Sub-Zero: Does his throw where he freezes the opponent and uses them as a surf board but jumps off midway sending the opponent slamming into the barrier and exploding into a million pieces.

Shang Tsung: Tsung morphs into Moloch and hits the opponent in the chest with his ball making the opponent torso fly off. And just for the hell of it, upon separation blood and chunks of flesh fly everywhere.

Quan Chi: Quan Chi grabs the opponent by their leg, places his leg on their stomach then pushes with his leg and pulls with his arm ripping the opponents leg off. Then he beats them silly with it while it is shooting blood all over the place. (MK4 Style)

Johnny Cage: Johnny Cage puts every attack he has into one long style branching combo with the shadow effect behind every move and at the end the opponent falls apart in a heap of ripped flesh and broken bones.

Cyrax (Joke Fatality): Cyrax hits opponent with his laser blade and they poof disappear leaving only their cloths behind.

Bo’ Rai Cho: Bo’ Rai Cho takes out his quarterstaff and lodges it in-between the opponents jaw and the roof of their mouth. He then looks up at a very high angel and begins to vomit. All of his vomit lands in the opponent’s mouth and they drink it all. He keeps puking until the opponent becomes severally fat and explodes send blood, vomit, bile, broken bones, and chunks of flesh everywhere.
And last but not least

Frost: She freezes the opponent making your game system freeze, catch on fire, followed by it exploding and burning your house down.