a phenomenon resulting when kids come back to school on a monday with haircuts such as buzzcuts, lawnmower cuts, and other unsightly hair cuts. the best way it has been described is that boys get together on the weekends and cut eachothers hair with lawnmowers.
Tina: oh, kevin's hair was so beautiful, but now look at it, it's a square!
Jess: it's atrocious! he must have gone to lawnmower weekend!