Deltarune
Following up on a series of cryptic, yet hopeful, tweets made yesterday from the Undertale Twitter account, a new game has emerged. It's called Deltarune and aside from being a clever anagram of Undertale, it seems to share a lot of similarities to its predecessor.

But you don't have to take my word for it. No, sir. You can try out Deltarune for yourself right now by visiting the Deltarune website.

SUPER IMPORTANT WARNING: It seems as though the uninstaller for Deltarune just straight up deletes the entire directory that the installer is in. So yeah, maybe don't use the uninstaller. You may want to just manually delete the game directory instead.