Big Hex

Big Hex is the only Mech pet, yet most people consider it as a Storm element pet (since it has Storm element moves). It can be added as one of your Buddies, so they can follow you around outside of battle.

More Info

 * Big Hex was the first original Epic, said to fight the Puppet Master alone. Until...Arctursus, Florafox, Magmischief, and Diveodile came along to help it out as sidekicks! Yet with their power, they still couldn't defeat the Puppet Master, and retreated to their statue form in the Epics Subspace. There, you can meet all 5 and learn about each of them (Macha will be your guide)
 * Big Hex is considered a Storm pet, because he is weak to Ice pets, and strong to Water pets.
 * Below are pictures of the figure (buyable in real life) and the in-game ad of when it first came out (its name was originally just Hex).