How to Terrify Your Little Sister's Friends

My friend recently informed me that her daughter, Avery (age 4) had asked whether she could have a play date with Jane.  This wasn't an unusual request; our families often hang out together.  Jane and Avery are excellent collaborators when it comes to (a) sweetly caring for their many baby dolls; and (b) viciously excluding Avery's little brother from everything they do.

A family get-together seemed in order - until it became clear that Jane was welcome, but the jury was still out on Claire.  The reason?  According to Avery, "Claire knows how to kill people."