Ambulance is the name of the phenomenon where normally inanimate objects become animate. Typically referred to as an "ambulant" item, these objects are able to behave in all regards as a living creature. The most well-known example of ambulance is ambulant furniture, but all manner of objects may become ambulant - typically when an individual has a strong attachment to an object for a long period.
Buildings, clothing, and frequently carried items are all typical objects that suffer from ambulance. In many cases an ambulant item will become unruly, unusable, or both - this encourages citizens to frequently replace items they've had for a long time. While typically ambulance happens over time, it can be induced with intentional magic usage or randomly by the City's chaotic nature.
Given that buildings by their very nature are susceptible to becoming ambulant, Nodd has many ways to deal with it. Architects deal with the issues caused by ambulant buildings regularly, and possess a myriad of spells to control and pacify buildings. Similarly, The Pruning and Sporefall are events designed to combat ambulance in buildings. These events take place each turn, destroying old buildings and seeding new ones respectively. While populated buildings are typically safe to live in even while ambulant, the lack of regular control rituals makes abandoned buildings incredibly dangerous - hearthhunters must be well prepared to delve into these locations.