Meet limax maximus, aka the leopard slug. We found this fellow crossing a footpath late at night in upper Manhattan. It was about 6" long, and could move roughly that far per minute at top speed. My friends, worrying the torpid mollusk wouldn't finish his crossing before meeting with a human foot, generously gave him a lift. A passerby said that she saw huge slugs like this during her time in Fukushima after the nuclear disaster there, but this one didn't seem particularly radioactive.