My roommate is really possessive of his peanut butter, iin?

Is it normal that my roommate is really possessive of his peanut butter? It all started when I took it out of the cabinet one time to make a sandwich and he thought I was trying to steal it. The next time we went grocery shopping, which we always split the cost for, so it was my peanut butter too, he said we shouldn't buy any more peanut butter, so I said that was okay. Then later that week I opened the oven to put in a casserole and there was peanut butter hidden inside. He is always hiding it in different places. I've found peanut butter in the freezer, I've found peanut butter behind the couch, One time I opened the dishwasher to put the dishes back and there was peanut butter all over everything and I asked him what had happened and he said he didn't know what I was talking about. This is seriously getting out of hand. Is it normal?