Update: A great many of you picked up that this was an image from CoH, but I think reader Brigand wins the comments this afternoon by not only telling us what game, but also giving us a detailed rundown on the location and the fight. Says Brigand:
...our tentacular friend there is Lusca, the giant octopus. She's a Giant Monster that requires several full teams of heroes to take down.... You assault her one tentacle at a time, while trying to avoid the fury of her other flailing appendages and the blinding ink-cloud she spouts from her head. After all of the tentacles have been destroyed, you close in for a final battle with the head.
Do you have a screenshot of your own that you think expresses a unique or memorable moment in your favorite MMO? Send them to us with a description (including game name and location) and you may see it posted here for tomorrow's One Shots.