I gave my friend a knife. She can use it to teach her kids a lesson.
Why would you let kids play with a knife? What do you think will happen?
I put on some background woods and some soft music as my friends woods and some soft music as her kids
Best case scenario is you want your friend to scare their kids with the knife. That's terrorizing in itself and could scar the kids for life.
It's only a toy knife. How can that hurt anyone?
Even a toy can look real. If they kids think they might die they will be scared of people holding them or strangers that remind them of the situation. Heck even they could have nightmares for ages because of this.