A new game mode.
A gladiator type dealio. 2 teams of 6 pick champions (can't be the same, also would take place in a draft) They get half-build then 1 person from each team would be sent out randomly on Howling Abyss then once one champ (or in some cases both) dies they get chucked into spectator mode. Then another round of champs gets sent out. This keeps happening until on side runs out of champs.