VIDEOS:
The Gleam Eyes
A Dungeon Boss on Floor 74 in Sword Art Online. Kirito managed to defeat it on his own. Cut to next season where Yui manages to use the SAO Code already-present within ALfheim Online to transform Kirito's Player Avatar into The Gleam Eyes in order to fight against a group of Salamanders trying to kill them.
Example of:
Defeat Means Playable