This time, it's less uncomfortable and more overwhelming. Frisk feels so small, at least on the surface. But their soul seems bigger and brighter than ever. Whereas Sans has grown too big to do much of anything but sleep and pace and kill, but inside he just feels lost within his own body. Like being left in a house that you used to live in but moved away from years ago.

Sans closes his eyes and stays still. He's still basically a skeleton, and nothing can stand still like a skeleton. "...good," he rumbles in reply. More at the promise to be careful than anything else. Frisk is already doing more than Sans had even thought possible to help keep him from forgetting, too.

At the expected question, he sighs just a little, though the exhale still disturbs the grass at their feet. The reasons are rather technical, the explanation is long and depressing, but Frisk probably isn't actually asking about any of that. At heart, it boils down to one thing.

"Accident. With Gaster."