The Crystalline Crushblat mostly sit in an idle position, only moving when it senses Pikmin or Olimar nearby. It will then slowly walk to them and attempt to crush them with its crystalline body. The armor can be destroyed by Rock Pikmin rending him vulnerable to other Pikmin, when this happen, the Crystalline Crushblat will try to run away in the opposite direction.
Hey! Pikmin Log
"It's aggressive while encased in its crystal shell, but runs away quickly if that shell should be broken. That behavior seems familiar...I think I know someone on Hocotate whose personality changes depending on what they're wearing."