Welcome back to Undertale.

It's time.

Dear Gaster, 

     Hey, it's Sans. It may be nothing but I'm a little worried. I was checking the timeline, as usual, and everything seemed normal, but I found a small rift. It doesn't seem big enough to change anything. It might change a monster's birth date or name. I know it's probably nothing but can you maybe send me a book or something to make sure it's nothing I don't want this to ruin out final "Happy Ending".

                                                                                                                                    ~Sans the skeleton