We also dont know exactly what sort of shield evil squidward has. It deflected her energy beam, but it seemed to bend it around the creature. Would it stop a physical attack? Could maxima act as a giant cannonball and smash it in the face? Or would her body bounce off or flow around like the energy beam does? Might be best if she hurls a rock at mach 12 at its face and sees what happens there first before trying it herself though. It IS possible its an energy blocker only after all. When you are facing an enemy army known for solely using lasers and such as weaponry, you protect against lasers and dont waste money on ballistic defenses.