This has just been confirmed canon via the 10th anniversary stream

[quote]"yand":/users/793638 said: calling Cave Story "Undertale zero" upsets me [/quote] Agreed.

[quote]"wickysticket":/users/1324217 said: Wi-fi [/quote] mobile data

story of toriel

Metamorfose

Can't wait for undertale two, also called undergroundbound in japan

toriels evolution line

calling Cave Story "Undertale zero" upsets me

[quote]"wickysticket":/users/1324217 said: Wi-fi [/quote] Russian nesting dolls

Wi-fi