"Llevarse el gato al agua" means, "To take the cat to the water." Not an easy task, right? This phrase means someone managed to do something very difficult.
from Matador Network » Matador Network http://matadornetwork.com/abroad/12-phrases-spaniards-understand/
from Matador Network » Matador Network http://matadornetwork.com/abroad/12-phrases-spaniards-understand/