A derogatory term.
Used to
address someone (usually but not necessarily of
black origin) to infer that they are very very
stupid.
Also used as a greeting among some circles.
In English footbal - "How did he miss that header the Spastic-Koon!"
or
"Look at the mess you've made of my
car you Spastic-Koons."
or
Bill: He's driving a bit quickly,
Dad.
Jim : It's these Spastic-Koons, son, no respect for rules...