An Undertale AU (Alternate universe) were all of the main Undertale AU's (Underswap, Underfell, Storyshift, and Outertail) and Undertale are amalgamated together in a way that the monsters are all amalgamates of themselves from AU's combined with Undertale just like the amalgamates in the true lab creating many horrific creatures out of your favorite Undertale characters

A portmanteau of carpe diem, a Latin phrase that means “Seize the Day!” and DM, which stands for Direct Messages. This word means seizing the day via DMs.

a weird-ass Undertale AU that's supposed to be scary by using amalgamates, but isn't scary at all. just awkward.