Gruesome Twosome
This is Phantom Couples Twosome in a 2x8, resulting in a virtual setup
which is parallel waves. The point of this concept, aside from the funny name,
is that the starting setup is always taken to be a 2x8, instead of the 4x4 that
concepts like "Phantom Couples Twosome" normally indicate. That is, from
normal parallel 2-faced lines, Phantom Couples Twosome places the phantoms to make
a 4x4, so the virtual setup is columns. Gruesome Twosome places the phantoms to make
a 2x8, so the virtual setup is parallel waves.
"Gruesome" is also used with other couples/tandem concepts, as in
"Gruesome as Couples" or "Gruesome Tandem Twosome". In general, it directs
that the phantoms be placed to make a 2x8, and that people be associated in
pairs parallel to the long axis, creating a virtual 2x4.