The house that Paulina (the cow) built

Now I know what builder Ice is using on the lot near his parent's farm

Three simple steps to Antón García-Abril's Trufa house:

1. build a house shape out of hay bales
2. pour concrete over the hay bales (and dirt over the concrete)
3. Let loose the cows! – in this case, one cow, Paulina

To empty the interior, the calf Paulina arrived, and enjoyed the 50m3 of the nicest food, from which she nourished for a year until she left her habitat, already as an adult and weighing 300 kilos. She had eaten the interior volume, and space appeared for the first time, restoring the architectural condition of the truffle after having been a shelter for the animal and the vegetable mass for a long time.

And yes, there is video.

Via io9.