When they were 12 years old in 2014, Anissa Weier and and Morgan Geyser stabbed fellow member of their social circle Paxton, called Bella, ostensibly in tribute to Slenderman, whose acolytes they wished to become. The seductive, illicit thrill of the relationship between Weier and Geyser, as well as the motives entangled in a shared fictional universe, reminds me of the 1954 Parker Hulme murder case. The same key elements — two girls causing harm to someone, with motives entangled in a shared fictional universe — call the comparison to mind, though Parker and Hulme were older [15 and 16], and they successfully killed Parker’s mom. It’s interesting that paracosms figured into both crimes, although I have no conclusive thoughts on the subject.