After yesterday's tease about a new announcement, we finally learned that Undertale's Toby Fox revealed a new demo called Deltarune. A few tweets were posted this morning on the game's Twitter account, all containing some weird and cryptic messages, all eventually leading to a final post pointing people to Deltarune.com. The website takes you to a downloadable demo that will require you to basically bypass a lot of your PC's safety features to download if you wish to play it. What you get, keeping things as spoiler-free as possible, is a game that looks and feels like Undertale with some changes.
You can download the demo for Deltarune (which if you haven't guessed already is an anagram for Undertale) completely free.