I had this encounter idea back for along time, but never really got a chance to work on it. Following The Colossus of Laarn article, I got a bit more inspired to finish it. Bare with me for a few lines while I give you a setup for this campaign arc.
Here is the basic setup, basically the party needs to investigate rumors that a powerful relic was discovered off the shore of Khorvaire, and removed from the ocean. THe groups task is to acertain the nature of this relic, and what value it could have.
Now you could fill in the blanks of who is sending the group on the mission, and where this relic was excavated from. Both groups would probably need a fair amount of rescources to remove a large relic from deep off-shore.
The search for clues, and digging into territiory could be interesting too. Perhaps this relic is having unique effects/powers to the neighboring populace.
--Okay so finally you learn more about the relic, and all its effects it is having and you come onto the relic....so what is it?
The relic is a giant rune covered titan of the age of Giants, who is now petrified stone. Perhaps it was a great leader amoungst the giant tribes of old. The death of this giant seems apparent. He is embracing a huge skeletal dragon, who's tail happens to have empaled the giant through the chest. Both seem to have parished, but something seems unusual about the giant having turned into solid rock. And how did this thing come so close to Khorvaire, perhaps it flowed from another continent, or these two were fighting in a deadly aerial battle and crashed in the ocean after inflicting mortal wounds.
The group, for perhaps numerous reasons, fights the current holders of this relic. Their battle begins unleashes magical energies that seems to be causing a stir in the relic. Suddenly the skull of the titan glows, and becomes animated. Encased in a roaring flames, it begins hovering around the relic, speaking in ancient tongues to all around.
Now comes the part I am trying to figure out. How does the group stop this thing? It is faily impervious to damage, and is extremely powerful (right now I have this set-up as probably a low-paragon level encounter.)
Any ideas would be welcome, because I do want this to be a skill challenge.
-Perhaps there is something about the dragon that can be used (perhaps part of the challenge could be in trying to reanimate the dragon to temporarily fight the skull for you.)
-Maybe you need to get the skull to attack its body enough times, destroying it.
For a different approach, let there be a vehicle or a siege weapon-perhaps a fully equipped ship or airship. The players in this version realise or are informed that they can't fight the skull themelves, but victory might be possible if they use the ship. During the skill challenge they must make the correct maneuvers piloting the thing, succesfully targetting and shooting, perhaps raising the crew's morale or fighting the flames as well.
That's all I can think for now.
Last week I run my version of the The Colossus of Laarn (mine was a colossus Dhakaani hobgoblin somewhere below ground in the Valenar), the warlock in the party used Sequester power on it which sent the colossus into a demi-plane, I rolled with the idea and that become the solution. tho they are going to read in the Korranberg Chronicle in a few days that a hobgoblin colossus mysteriously appeared and drooped over Shan.