The escalating sound produced by a large group of tweens. At first, the sound is a light chatter. Then it grows in intensity and the frequency changes to a squeal. Eventually the incoherent ramblings of these little pricks drowns out all ambient background sound until you get a massive migraine.
After my buddies and I walked out of the movie theater we noticed a large group of tweens waiting around for mommy and daddy to come in their BMWs & Lexus to pick them up. Their tween spastics were so deafening that we started to bleed from our ears.
Spasticus is an alternative way of calling someone a Spaz, Retard, or Fuck Face. The word orginates from a song by 'Ian Dury and the Blockheads' in which the lyrics largely consist of : "I'm spasticus, I'm spasticus
I'm spasticus autisticus"
The main bonus that you get with the word 'Spasticus' is that you can spontaeneously burst into song.. singing the 'Spasticus Autisticus' song, and relatively few people find it as offensive as just calling someone a retard straight off.