Stockholm — A Swedish zoo has been partially shut down after a king cobra staged an impressive escape from its enclosure at the weekend, with staff on Monday still searching for the venomous vagrant.The snake, named Sir Vas (Sir Hiss), escaped on Saturday through a lamp fixture in a terrarium and was believed to be somewhere in an inner ceiling.They have also brought in special cameras designed to inspect sewage pipes, in order to search the nooks and crannies out of reach.He explained that the escaped snake had an advantage over previous tenants: staff had recently replaced the lamp at the top of the enclosure with a low-energy bulb."But now it's not hot at all and the new king cobra discovered this and wedged its head in between the lightbulb and the light fixture and managed to push itself out.""