I think Mythic might be the solution, especially since you can take their tiers away once the threat is over if you aren't comfortable continually using it. As for another solution.
Thanks, Rakshaka. I've benefited hugely from your suggestions on this thread. I'm going to see if I can study the Mythic Rules this week. My main concern is that Pathfinder is already pretty rules intensive, so adding on the Mythic rules may just lead to overload. But I'll see if I can figure it out. In any event, I don't think I'd want to give them the "Hard to Kill" aspect of the Mythic Rules...
I looked it up and according to a ruling Vital Strike and Spring Attack work together. Does this mean that the Colour out of Space should be doing 12d6 damage per round?
I'm concerned that my casterless party is going to get dissolved tomorrow and thought I would ask if that is what everyone else did.
My party was scared off from exploring the hallway where the Colour was. I'm going to have to figure out some appropriate consequence for their failure to get rid of it (any suggestions?), because I think the module specifically says something about it being released at the end if the PCs didn't get rid of it.