On an alternate earth, lethal Pliosaurs size creatures infest the ocean, making sea travel impossible. Their cousin species tries to invade the surface every five years. The advantages of this monsters are:
- Healing factor: The average creature has a healing factor allowing it to survive life threatening injuries.
- Superior Strength: the average monster can lift 4,000 lb (1,810 kg) on a bench press, and have a bite of 3,700 PSI.
- Superior Speed : They can all run at about 80kph (50mph) for extended periods of time.
- Hard Skeletons : Their bones are harder than alumina ceramics. Their teeth and claws can easily tear apart steel.
- Protective shell: Each has a shell that acts as armor, capable of withstanding knives and low-caliber bullets.
- High senses : Their sense of hearing is sensitive enough to detect even the slightest noise at 1 kHz, they can smell an enemy from 20 miles away, and have a vision that is eight times sharper than a human's.
- Numbers:They heavily outnumber the human population(with a population estimate in billions), for each human soldier they have three.
- Toxic fumes: Some units are capable of releasing a toxin so powerful that it is capable of killing an elephant in a few seconds, only to melt it down to its bones later.
That said, they have certain weaknesses;
- No sense of self preservation: They do not recognize obvious dangers or traps, they throw themselves into the meat grinder by the hundreds, the only exception is when they lose more than a half of their forces, in that moment they retreat to the ocean to resupply.
- Not very smart: The only strategy they have is to rush into the enemy without taking any cover, using their numbers to overwhelm the humans. They are a bunch of wild animals that use their instincts to survive.
- Lack of biomass : their healing factor is not magic. Each time they are injured, they burn energy to heal. Eventually, several injuries will end up affecting their performance and kill them.
- Radiation: radiation with its ability to kill cells is a great Achilles heel.
- Fire: Fire like radiation is very effective.
- Advanced technological enemy: Humany is more advanced than current earth with a couple of decades. The average soldier are genetically augmented to Olympian level. They also have developed adavanced alloys, exoskeletons, railguns, and high tech drones.
- Overhelmed senses: Their advanced senses are a double-edged sword. Loud sounds, bright lights, or strong smells can confuse or hurt them.
- Pheromones: A mixture of chemical substances are capable of attracting or distracting these creatures.
- Humanity have prep time
So the answer is: How can these people fight these monsters? What type of strategy, tactic or technology would be used?.