Yes, you get a particle effect, as with any potion. Did you not expect that? I was talking about you, yourself. I expected you to know you'd have a particle effect, but I guess you didn't. If someone is invisible, walks into your base, you aren't looking for it. If you notice it, you will, but you are invisible. I just spammed them in a town, and once things move around, you can't find them. I have no idea where the villagers ended up.