Riot released the skin - Pizza Delivery Sivir at PAX.
Note: the skin is only the design concept, and it may not go alive right now. It may even never go alive.
A net user leaked a sketch designed by MaTTcom, and he pointed out that MaTTcom was designing similar skins for Riot or Riot imitated his idea.
Riot's designers also answered many questions at PAX.
To see the full interview Here：Pizza Delivery Sivir revealed at PAX