Board Thread:General Discussion/@comment-26006155-20181229180615/@comment-32182236-20190126134003

I'm pretty sure Toriel was the only one who DIDN'T get called, and she left the Ruins on her own volition because she was getting worried. The extra time spent in the True Lab was probably enough for that.

But you also have to remember that Flowey was behind this. He's the one who convinced Papyrus to do this. It could be that he's behind Toriel coming back as well. This also means even if it was a call from Papyrus, he could have gotten the number from Flowey.