Fettecke (fat corner) was an abstract installation created on 28 April 1982. The artist placed five kilograms of butter in a corner of his art room about two meters below the ceiling in the main building of the Kunstakademie Düsseldorf. His motivation for the artwork came from the anticipation of Lama Sogyal Rinpoche, whom Beuys had invited on behalf of the Dalai Lama in Europe, and a seminar of the Free International University. In the period that followed, the plastic served as "a constant demonstration object."

In 1986, a janitor of Kunstakademie cleaned up the butter about nine months after the artist's death, not realising it was an installation. Johannes Stüttgen found the remainder of the artwork, around 2 kilograms of butter, in a garbage bin and conserved it under the title "Leftovers of a fat-corner destroyed by the state" (Reste einer staatlich zerstörten Fettecke). Stüttgen claimed ownership of the artwork, as Beuys had said "Johannes, I'm finally making your Fettecke" at the time of its creation. In a subsequent lawsuit, the State of Northrhine Westphalia eventually settled to pay Stüttgen 40.000 DM in damages.

In 2014, artists Kopys, Löffler and Schmal distilled the remaining fat into spirit in an art performance called Geist. The resulting liquor, which is said to taste like parmesan cheese, is presented in Kunstpalast Düsseldorf.