This is the origin story of the Urban Legend about poisoned Halloween Candy from the monster, The Candy Man. 

Resources:
https://en.wikipedia.org/wiki/Ronald_Clark_O%27Bryan
https://www.aetv.com/real-crime/the-man-who-killed-halloween
https://www.investigationdiscovery.com/crimefeed/murder/candyman-poisoned-halloween-candy-pixie-stix
https://murderpedia.org/male.O/o1/obryan-ronald-clark.htm
https://thecrimewire.com/true-crime/Pixy-Stix-and-Poison-The-Murder-of-Timothy-OBrien