Superman vs. Aliens and Predators
A Predator shuttle crash lands in Metropolis national park and 30 Xenomorphs (plus Alien Queen) come pouring out and are already painting the streets red. Three Predators (one is Wolf from AvPR, the second one is from P2, and the third one is from the first Predator movie.) The Predators see Superman flying into the city to stop the Xenomorphs and see the man of steel as worthy prey.
Superman is from Superman Returns and the Predators have prepared for him. Their spears have kryptonite tips, shards of kryptonite are embedded into their smart discs, they have their iconic shoulder cannons, and they have their wrist blades made of kryptonite and the Predators can turn invisible whenever.
Technically, this is kinda like Superman vs. Aliens vs. Predators, so if Xenomorphs do detect the Predators, they're gonna attack them.
Will Superman save the day or will his head be placed on a trophy wall or will he get torn a new one by the Aliens?