Asriel hadn't gotten far in his attempts at mobility, but he's curled on his side by the time Sans arrive. His panic has somewhat subsided once he sees a fish tail instead of a flower stem, but it doesn't really make the situation better.

The voice is familiar, but Asriel glances up warily at a human figure he's never seen before. Another friendly castle resident? At least he hopes. There were plenty of people here that Asriel has yet to meet.

This isn't how Asriel wants to meet anyone though.

"No, but... I'm stuck."

To demonstrate, his new tail flips back and forth, but Asriel isn't moving.