At one time allies could can enter another player's nydus network, but allied zerg networks could not be linked The overseer could create a nydus worm after a nydus network had been produced as of October 2008. This ability cost energy. The overseer lost the ability to make nydus worms as of March 2009. In June 2008, the nydus worm was built directly from the nydus network, a point on the creep is selected (it could only emerge onto the creep) and the nydus worm erupted. By August 2009 it was produced from the network again. It has since become a stationary structure.