X Sp. Def 6

It raises the Sp. Def stat of a Pokémon in battle immensely. It wears off if the Pokémon is withdrawn.

X Sp. Def 6 is an item used in battle in PokeMMO.

How to get X Sp. Def 6 in PokeMMO

No GTL price and no known wild Pokémon for X Sp. Def 6: it comes from elsewhere in the game (shops, rewards, events).