They were unaffectionately called "lawn darts" by many U.S. pilots.
I remember those things being referred to as “flying coffins”; apparently they were a bear to drive. From the “Decoder” blog:
“Problems began to arise almost from the beginning of the introduction of the aircraft into Luftwaffe service. At the time of the introduction of the Starfighter in 1961, there were two crashes. An intensification of flying regimens saw an increased accident rate with the type. As the years progressed, so did the number of crashes in the type. The year 1962 saw seven crashes, 1964 saw 12 F-104s lost, and in 1965 nearly 28 aircraft were lost in accidents. The lost rate calculated to nearly two aircraft lost each month. In 1966, sixty one F-104Gs would crash claiming the lives of thirty five Luftwaffe pilots. The alarming rate of loss of the aircraft soon became known as the ‘Starfighter Crisis’ with alarming records surfacing. The Crisis would peak with a loss rate of 139 aircraft for every 100,000 flying hours. The unsafe nature of the aircraft in Luftwaffe service sent the German media into a feeding frenzy giving the type derogatory nicknames such as Witwenmacher ‘Widowmaker’, Fliegender Sarg ‘Flying Coffin’, Fallfighter ‘falling fighter’ or Erdnagel ‘Ground Nail’. The surrounding controversy over the accident rate of Luftwaffe Starfighters also led to the rather unflattering joke of How does one own a Starfighter? Just buy property anywhere in West Germany and wait and sooner or later one would crash into the property.
“The problem of the Starfighter Crisis, lie in the fact that the aircraft was extremely unforgiving in cases of pilot error and was extremely sensitive to control inputs. At the time of the types introduction, the F-104G was one of the most technologically sophisticated designs to enter service with the fledgling Luftwaffe and many of the pilots and ground crews of the Luftwaffe were accustomed to civilian jobs at the end of the Second World War. The lapse in aviation operations threw many pilots beyond the learning curve and they failed to keep up with the technological advances of jet powered aviation. As a response to this Luftwaffe pilots were sent to relatively short refresher courses in first generation jet aircraft which were underpowered in terms of the supersonic plus Starfighter. Luftwaffe ground crews were also introduced to the type with minimal to no maintenance experience on turbine engines, a reflection of the problem of national conscription into military service. As crews would come up to speed in learning to maintain the type, their service obligations would be completed and they returned to civilian life requiring a new technician to learn the maintainers course from the beginning.”