Unown G

Shaped like ancient writing, it is a huge mystery whether language or UNOWN came first.

Poke-POWER — GUARD: Once during your turn (before your attack), if Unown G is on your Bench, you may discard all cards attached to Unown G and attach Unown G to 1 of your Pokémon as a Pokémon Tool card. As long as Unown G is attached to a Pokémon, prevent all effects of attacks, excluding damage, done to that Pokémon.

Hidden Power (50): If Unown G has any damage counters on it, this attack's base damage is 10.