Definitely Dylan's idea (or so I think anyways). Dylan was talking about killing people and getting a gun way before Eric was.
I think Eric may have tried to recruit some of his friends, like Chris Morris for example, but either they weren't interested, or more than likely, didn't take Eric seriously.
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"I’ll see you in Heaven if you make the list"
Zachary Patrick Bowen (March 7, 1995-November 5, 2021).
I miss you little brother.