The explosions and starbolts each destroyed portions of Pride's monster, and he wishes he could have gotten more practice controlling constructs, so he could replenish that mass, but he cannot. To make the beast more convincing, he has it stagger every time it is hit, realizing that with the loss of mass, he has a good chance of losing, and so he would want to make sure they couldn't suspect that the monster he created was only a fraction of a greater threat. When the explosive bullets hit, and Starfire shot her bolts, Kimblee simply commented, "Badass."