SOE is experimenting on what it's calling "survival mode" for superhero MMO DC Universe Online.
According to a post on the official forums, the team is prototyping a wave-style event "where 8-player groups face off against waves of progressively tougher enemies and bosses," which ends with a full wipe and properly marks and rewards survival, though not in a way that makes the events "necessary to progression." Writes SOE's JackFrost,
We will return to an existing environment and use existing (but ever more challenging) enemies. Initially, we are planning to use Oan Sciencells, and feature a multitude of Lantern-related characters. Reusing existing resources means we can do this without impacting future content planned for DLCs. The event will likely be available only for limited amounts of time, cycling in and out of the game. It will not be attached to any DLC, but it will require a high (end-game) Combat Rating. Finally - and most importantly - it is intended to be a FUN, extra event for leagues and groups of players to throw themselves at, see a completely new experience in DCUO, and take real satisfaction in their accomplishments.Survival mode is early in development and subject to change; the developers have requested player feedback on the forums.