When Lightning and Mater fall down in the underground, they must find a way to get out safely. Along the way meeting new monster friends and a familiar face... Mater's Undertale is a crossover fanfic between both Undertale and Pixar Cars. If you're looking for an Undertale AU regarding the same premise (Mater's Tall Tale) then don't fret, as I will also be working on that too in the future! I'll be updating this fic whenever I can.
4 parts