We don't get it either, so don't ask us. The net on his head is "a gun that shoots metal parts at bad guys". The handle of the net fell off and now it's basically just a metal spike that falls right at eye or crotch level, depending on your age. So to protect the family from an unintentional skewering, Kerstin fashioned it with a Kinder Surprise egg case on the end. The mouth piece is a handle from Elliott's sippy cup.
Elliott went as a frog because we had a frog costume handy... not much beyond that. He seemed to enjoy the transformation and Halloween night was rainy... weather that frogs like.
Here is Alden with Elliot just before leaving for trick-or-treating.