It's still a physical manifestation of the Force, which the Vong are completely immune to. Of course, if the setting is favorable, Sidious could just smash him with debris, but in a fair location for the Supreme Overlord, I can see him possibly taking Sidious. Afterall, he and his elite are virtually impregnable in duels save for deep lightsaber or amphistaff wounds, and it stands to reason that if the slayers - whose skin was like armor, and mended itself quickly on top of that - could take multiple hits from a lightsaber, their only superior - bedecked in thicker armor and possessing unfathomable physical strength - would be able to do so, too. With his massive, formshifting amphistaff and incredible skill to boot, it's likely that he's capable of bringing down Sidious.
Originally posted by Swirly Girl
Yes, indirect attacks still work. What happens if he rips the ground from underneath him?
I suppose, but Shimrra would try and close the distance between himself and Sidious. With a staff that can change into multiple shapes and withstand lightsaber blows, I think Shimrra could take this one.
If he can withstand a high energy beam capable of cutting through various types of metals, I am pretty sure that he can take a couple of pounds of debris thrown at him. He could also dodge Sidious' attacks. It depends on how far away they are from each other.
By the time Sidious is screaming "Hahahahah" tossing things around, Shimrra would close the distance and start doing his thing.