Dangerous species under Mariana’s Trench will kill Humanity

As we all know the deepest known hole on earth is Mariana’s Trench which is 2550 KM deep and 69 KM wide. The pressure at the bottom is 1086 Bars which equals to 15,750 psi. If we want to go into the bottom, it’ll make us a paper sheet in just some seconds.
But there are some creatures living normally at the bottom, so is there any chance of having some old monsters in it?
If you want to have a better idea how deep Mariana’s Trench is, here is an illustration. If you placed Mount Everest at the bottom of the Mariana Trench, the peak would still be 2,133m or 7,000 feet below sea level.
Located in the western Pacific east of the Philippines, the trench is a crescent-shaped scar in the Earth’s crust.
It was formed through a process called subdiction. Earth’s crust is made up of comparably thin plates that float on the molten rock of the planet’s mantle.
While floating on the mantle, the edges of these plates slowly bump into each other and sometimes even collide.