You know why our housekeeping is sad? Because during one of the very infrequent vacuuming spells in our house, we actually found dried cat barf behind the couch.
Wow, we get both undigested cat foot barf (kinda splatty) and hairballs (those long tube-shaped things). At least I think that's what the varieties are. Poor kitties. My vet friend told me to feed them lots of Petromalt.