A uni housemate used MY deep-fat fryer (never asked if it was OK or indeed a wise thing to do) to try and make cheesy peas (anybody remember the Fast Show?)
He also did the washing up once and absent-mindedly took the cordless kettle off its mains-connected base and plunged it straight into the hot soapy water (exposed electrical connection socket down).
He was also given a great condition but somewhat vintage microwave/combi oven by some friends. We'd agreed to help with a hospitality welcome event for Freshers' Week and were doing jacket potatoes for a dozen or so recent arrivals.
He didn't realise that the knob on the oven was in Fahrenheit (didn't cross his mind at all to wonder why it went up to over 400 degrees), so he ended up feeding these poor, shy freshers - still all missing their mums' wonderful home-cooked cuisine and unfamiliar with, shall we say, less-accomplished skill levels - rock-hard potatoes that had been 'baked' to the same extent as they would have been had they been left in a cooled-down mug of tea for an hour or so.
They all politely thanked us and said how delicious they were before they left - and we got on with tidying everything away, including chucking a dozen uneaten potatoes straight into the bin....
Another housemate liked Weetabix and kept a big supply of it in a huge plastic tupperwear-type box.
Nothing weird so far. Except that he would take the box in to the bathroom every morning and sit there eating from it (no milk or spoon) whilst he was, erm, at ease.
The bathroom wall was thin and the door didn't fit in the frame properly, so we could clearly hear the simultaneous dry-crunching, scoffing, grunting and plopping going on. I presume he was aiming for peak efficiency by turning himself into a human perpetual motion machine.