So, I'm in the Battle Hall one night, my Shiny Gengar kicking you know what and takin' names,
and this guy with a Shedinja shows up.
(to be honest, I wasn't familiar with Wonder Guard @ the time.)
And I was amazed, this thing blocks one attack after another.
After what seemed a long time, My Gengar took it down with a Shadow Ball.
Whew, that was a tough battle, as I recall.