Notes:

Artist (DA): Jirris

Source

Description (Partial):
"Undertale! Come Explore the Underground with Frisk and his friends as he tries to get home! Adopted by the kindly Toriel and the wise King Dreemurr, Frisk learns lessons about friendship with the power of his magical friendship heart gem! Along with Captain Undyne of the Royal Guard and the bashful but brilliant Doctor Alphys, there's fun and adventure ahead!"

"The Evil Asgore will stop at nothing to collect all the friendship heart gems so he can take over the Underground for himself and the monsters of The Core! Helping him are his devoted but bumbling skeleton minions, Papyrus and Sans. Asgore is determined to get the friendship gems to finish his ultimate creation, the maniacal musical computer Mettaton!"

…

I basically imagine this show would hit all the high/low notes of cheaply made 80's cartoons. A really pretty opening with a catchy themesong that explains the plot. Mushy animation with jittery cells. Captain N levels of completely screwing up the source material and character designs. The badguy shaking his fist at his minions and calling them dunderheads because they didn't get the macguffin again. Painfully forced moral lessons at the end of each episode (given by Toriel, because who else would you pick for that job). Angry rabblerousing by the religious right because goat-people look too much like the devil.

Basically it would be horrible.