"Here we are," Grimzo says, his tone noticeably less jovial than you'd all come to get used to. "Might want to step back a little."
He drops to one knee, removes his backpack, and takes out a small wooden folding stool, which he sets on the ground, and a small black figurine of a dog with copper eyes, which he sets on the stool.
"We are here," Grimzo says in a barely audible whisper. "Come forth, come forth. Your sister wills it. Your mother permits it. Come forth, Wigludru, come forth."
Your torches flicker as something like a great cold shadow passes over you. The stool tips over, and the dog figurine is no longer there. Grimzo draws a sharp breath.
Something massive and black coalesces next to the white wall. You can't make out its exact form, but it starts to move: armlike shadows rear back and swing down hard into the wall. White dust and rootlike fragments spray out as the shadow tears into the wall with rapid, unrelenting blows.
Would anybody like to do or say anything while the shadow-thing is attacking the wall?