I had created a portal from the Nether to the Overworld. A creeper entered it. I used a Splash Potion of Invisibility Extended on myself, confirmed that it had taken effect by pressing "E" and stepped through the portal. As soon as I appeared in the Nether, the Creeper triggered, blowing a hole in my shelter and snuffing the portal.

What I expected to happen was...:
I expected, at the very least, to have time to assess the situation and determine a course of action because the creeper would not know I was there. This was, however, the first time I've used invisibility, and I couldn't find anything about this being a known or expected result.

What actually happened was...:
The creeper acted exactly as though I were not invisible and did what creepers do.

Steps to Reproduce:
1. Make sure you're in Survival on Hard
2. Send a Creeper through a nether portal from the overworld
3. use a splash potion of invisibility extended on yourself
4. step through the portal
5. wince