Curiouser and curiouser

Well, on checking the oil today (which by the way, our car doesn't actually seem to use, but that's another matter), the Boy Wonder found a banana skin and a prawn cracker on top of the car battery. We have come up with several possible theories on how this could have happened, but basically none of them make sense except the idea that someone with access to the car and keys popped the bonnet and put them there, presumably for a prank.

We know it wasn't left there when it was shipped as we had to jump start it three times to get it out of the port, and it couldn't have been done without popping the bonnet from the inside as the clip isn't broken. But, if you had access to the keys (which several people would have done) and wanted to play a prank, why make it something so obscure and such a rubbish prank? Why a banana skin and a prawn cracker? Why leave them in the engine where they are quite unlikely to be found? And another few 'whys' just for good measure because everything about this is weird.

So, until we can find out what happened, this will be consigned to the 'inexplicably mystery' files, along with the unfeasibly massive bird poo we once found on the windscreen, the unexpected turning up on TV of two friends who we didn't know even knew each other and the time we met someone the Boy Wonder knew from childhood in a laundry room in Canada.  Let's hope that the quest for answers turns up something so we can close this case before it drives me mad.