Blissey had a breakout performance at worlds, taking 2nd place in the senior division, piloted by Paul Atanassov. It received play at autumn Battle Roads and a smaller amount throughout the season.
You began with Chatot MD several copies(2-4 usually) to refresh your hand(Mimic, or Copycat in attack form).
You then had a pretty thick line of Blissey MT (usually 4-4), with it’s seemingly limitless damage cap and large HP (130).
It also utilized a bunch of disruption (Cessation Crystal, Energy Removal 2, Crystal beach)
Very tanky deck, and was overall similar to Seismitoad-EX based decks.