Epic Sn(f)ail?

This mollusc spent last night climbing up a door. The top of the door is about as far as it can get from a source of food in my garden. After the door, its got a few metres of stone to go before it reaches the roof - where there might be a little moss to eat. Are we looking at a new form of super snail here, or is it rather a case of a lousy sense of direction giving it the worst possible start to a Monday?