Strange Case from Waukesha, Wisconsin wherein two 12 year old girls stabbed another girl nearly killing her.

Two girls, 12 years of age, repeatedly stabbed another girl almost killing her.  The stabbing victim miraculously survived.  The strange part of this story is that the apparent reason the two defendants stabbed the victim was to appease the "Slender Man."  It was a mythical forest being that for some reason they believed was real.  Now aside from that obvious strange issues, why would the two 12 year old girls be charged as adults?  Obviously they are delusional if they truly believe in the Slender Man.  Secondly, they are well below 15 years of age, the age typically seen as a cut off for adult charging purposes.