Your view is stuck in one position when viewing a mob's point of view and the mob turns.

I was viewing a creeper's point of view in a mineshaft and when the Creeper turned around, my view was still looking at a pole.

[EDIT]: This happens to ALL mobs in Minecraft. I was testing on Villager, Ender man, Creeper, Spider, Chicken, Giant (using /summon), and Zombie and all did the same thing