Okay, so basically, I'm going to try to take any canon clues I can find to come up with their reactions to the ship. It will follow the same order as my own opinions if you want to compare or something, xD. But this is all for fun! I don't even know if I'm gonna portray them right, but...HERE WE GO!

Undertale Sans... Underswap Papyrus... Storyshift Chara... What could go wrong?