Any kind of predator that thinks of itself as an Apex would not like another predator claiming the same title in its area, and if both of them were to ever meet then they would fight till one of them dies.
That is what was happening as a Giganotosaurus and a Spinosaurus coincidentally came to the same area to hunt.
The fight would have never started if one of them bowed their head accepting the other to be stronger than them, but both of the beasts didn't want to back down.
Neither the Spinosaurus nor the Giganotosaurus wanted to bow their head which meant that there was only one path left and that was a fight to the death.
The giganotosaurus looked just like the last one, but it didn't seem to have the ability to shrink in size rather it had the ability to harden its body.
The Spinosaurus on the other hand seemed to have the ability to shoot poisonous stingers from its protruding spine.
