Reminds of this time at school.
This kid had found a WWII hand grenade in his garden at the weekend. Anyway shows his dad who did nothing, so he keeps it and polishes it. On Monday he brings a live grenade 45 years old too, in to school, on the bus with 50 other kids. Then he and his mate play "bounce the grenade" off the wall.....
Apparently the pin broke but jammed. Takes teh thing to class and shows the teacher.
End result, we got a day off school, he got his head seriously kicked in.