Yep bolt 'bombs'! Use 2 bolts & a nut holding both, fill void with match heads & screw finger tight.
Hide behind a brick wall whilst throwing it at a far corner - they go off with a fair old BANG & it separates the 2 bolts at bloody high velocity!
Note to all who dare try this......watch out as they travel a sizable distance with considerable force! Yeah we used to do dumb things as kids!!!!