Mextel the boss of the mall. He sits in a mini-bulldozer and will try to run you over in battle.
For most of his turns he will be charging up for an attack. Pay attention to character dialogue to see who he is targeting. Then use either the Knight's defense or the Ninja hiding ability to protect that person (ninja allows the character to avoid 1 hit, so that is the best option).
Mextel is not joined by any other enemies, so your stamps should be things that maximize damage to a single target.