Super Mario 64 (U) [!] modded_8019C828 is a ROM hack made by biobak for the Creepypasta Competition in 2019, in which it placed 4th.
This hack comes with a document for the player to read. This document has been transcribed to this wiki for archival purposes, and can be found here: Super Mario 64 (U) ! modded 8019C828/2015 Archive - sm64hacksarefun.