Creepers, definitely creepers. I had just made it to the Applied Energistics phase, otherwise known as the NO MOAR CHESTS!!!! phase... and was packing everything into AE for my big move (my big expedition to go find a suitable place for a permanent base)... however, I forgot to put the 2 blocks of cobble to shut my front door, and I lost track of time in my little temporary cave and didn't see it was now past sundown... I turn around and what do I see? A creeper, standing right next to my AE setup. Oh yeah - he didn't come right at me, I swear to goodness that madman went right for my AE as if he knew it held everything in my entire world... literally.
I tried to dash at him while pulling my sword, but it was too late, it was inevitable... my entire world, everything but my own life, went up in a big BANG! When the smoke cleared, I saw my 6 hard drives lying on the ground and I gathered them up. They were safe!! But... I had no ME controller, no ME drive, and no ME access terminal. They had evaporated in the creeper attack. Same with the redstone energy cell and most of the redstone conduit - gone. And all my TE3 machines and ingots were on the hard drives. AARRGGGHHHH!!! lol (Epilogue: I had enabled cheats when I created my world so I just went to creative mode and "re-obtained" my items that I lost. No need to fret. It's still a funny story tho!)