When breeding wolves, if there is a nearby skeleton, the wolves will ignore each other to pursue the skeleton.

Duplicate: Obtain 2 tamed wolves and have both enter love mode by feeding them near a skeleton. The wolves should pursue the skeleton before a baby wolf is created. This has been observed to occur even when the skeleton is not within a clear line of sight of the wolves (i.e. outside of a building the wolves to bred are in)

Not tested with other hostile mobs.