Creeper AI seems confused

I was playing in creative, building a house in the mountain biome, when there was suddenly a creeper behind me. At first, I think nothing of it, probably just an area I forgot to light up, as I'm in creative. But then, the creeper explodes on me, plays the hurt sound, and I take knockback. Part of my house was destroyed and so was the ground around it. This was really confusing, because I know for a fact that you aren't supposed to be attacked in creative. Please do something about this.