Black Thumb, or Sabotage?

Ok, so I'm not known for my green thumb... I know it partially has to do with the fact that when I purchase plants, I usually tend to buy the saddest, most scraggly ones, because I feel sorry for them that nobody else will adopt them. However, over the last few months, Mom has started me a few herb plants that are perfectly healthy & alive when I get them, but are completely dead within a couple of weeks. I figured I wasn't watering them properly (too much or too little?), so I got some of the AquaGlobes to do that part for me. The last one she gave me, Molly the Mint, is technically still alive, but is in a pretty sorry state:



Then, the other night, I think I discovered the source of my black thumb!! I caught MAX eating the leaves!!! I haven't been able to catch him on camera, but there were a few white hairs left behind as evidence. Has he been eating all my plants, or do I really end up killing them all?