The term 'Spack' is used to describe someone who above all else, proven to be exceedingly dimwitted, this person isn't a few sandwiches short of a picnic, oh no no no, they forgot the whole fucking picnic basket.
This is an insult best used on friends or people who you know know
the definition of it, because when used on an actual Spack, they will not know the sheer gravity of the insult that has been dropped upon them due to their lack of
intelligence, and therefore the impact of the insult is lowered
significantly.