Acquiring Pets 64 is a hack made by someone2639 for the Creepypasta Competition, in which it placed 10th.
It is based off of an urban legend popularised on YouTube by a channel called Petscop, that has posted videos "showcasing" footage from a game that does not exist.
While there is very little first-hand information regarding the nature of this urban legend, there is a substantial amount of anecdotal evidence suggesting that it is based off of real events surrounding severe child abuse. Please bear this in mind if you are considering doing further research into this urban legend.