Now that Shack has made a comment I would be happy to say that he is right.
There were several of these 'mines' dropped in 1940/42. They were called 'Aerial Torpedos' or aerial mines or parachute mines because they arrived on a parachute. One such incident occured a 100 yards from my home. This one was a 'torpedo' it hung up on a tree, in a fairly strong wind and soon dislodged itself and blew up three houses with nothing more than lost possessions and lots of broken windows. Bad enough but another also got hung up in a tree near my school and we wanted the parachute, or at least some of the cords which made great belts. A policeman (silly man) after clearing everyone at least a 1/4 mile away went up the tree to secure it. Sadly he failed and it went off this time scattering 2 or 3 smaller mines.
We were lucky because the reality was that a 1/4 mile was not nearly enough - half a mile would have been better - but no-one was injured except the policeman who was never found. Whole anyway.
Later the bomb of the day was the 'butterfly bomb' which, if you picked it up, opened its wings and exploded.
The Japanese tried aerial mines, shaped like a torpedo. Close to the ground it opened and out flew a lot of smaller ones. Bit like a cluster bomb. Don't know much more about those.
PPP