While strip mining with a friend, I found a cave and went exploring. While in the cave I was attacked and poisoned by a witch. Our difficulty was set to normal so I should just be left with half a heart. Knowing this I ran off to a different part of the cave and enclosed myself into a 1x1 space. The witch followed me (or another one spawned) and was standing near the area I had blocked off to heal. My friend went to attack the witch and she continued throwing potions. Because we were so close in proximity the witch was still able to harm me with her potions and I died as a result. My friend ended up killing the witch and I ran back to grab my stuff since I had never left or broke a block within that 1x1 enclosure. When my friend mined out of the area where I was, all of my things were gone except for my armor. The only thing my friend picked up was my experience. I had a full inventory of food, wood, minerals, and tools. Everything was gone. My friend then mined out more blocks to see if maybe it clipped through, but everything was gone.