Talk:Hound/@comment-91.156.128.47-20130530162342/@comment-65.24.209.161-20130530221438

Hounds (and occasionally other mobs) were becoming unbound when you reentered your world. Since the old group were unbound, a new group would spawn. Each time you reentered, the count would go up by 2.

This bug has been fixed though, so what you encountered are just the remnants of the bug. Since you cleared the remnants your game should be reasonable again.