I had a crawfish about his size when I was a kid that escaped from its 10g tank. Mom ran into my bedroom at 5:30am yelling at me. Turns out he'd made it out of the tank, down from the 4+ foot armoire the tank was on, across my floor, down the hallway, and was still making a break for it across the dining room floor. Got him back in the tank, a few weeks later "he" spawned a bunch of tiny crawfish (guess she'd mated just before I caught her). They really are tough buggers.