The Mammotuff has 25 million hp and 300 defense. The Mammotuff had exploitable weak spots that should be used for your advantage

The Mammotuff is 11 meters tall (taller then the Murdertrodon but smaller then the Demonic Shingod) The Mammotuff has a plasma cannon on top of it's back and has super powerful tusks and a very sharp snout. The Mammotuff has insane armor making it able to shrug off hits like it nothing

The issue with your bosses: you give them weak points
And no thorns

They are ment to have weak points because they are based off the game Horizon: Zero dawn and Horizon: forbidden west. In those games the enemies and bosses have weak points

Oh ok

Tyrex: I think I can take him on?