Alien Creatures?

When I was 17 I worked at a summer camp, there were a sister and a brother who attended, Wyatt and Vivienne; they were adorable and extremely smart for being so young. I remember being kind of shocked at the intelligence/maturity level they had, which is why I never doubted what they told me.

They came to me separately and described the same...things... They had seen walking around in their house/hallway and in the yard. It was weird. I asked for a description from Vivienne, who told me about it first. Her brother Wyatt told me the same thing at a different time that day and in a calm, logical manner.

They saw them while playing marbles or some game like that.

The story didn't seem rehearsed, it just seemed as though it randomly came out in conversation with each of them, pretty casually. I asked all the right questions trying to help them dis-prove whatever it could have been but came up with nothing other than what they saw wasn't normal.

What they described, I can only picture looked like SOMETHING with a head resembling a bull terrier - that's what I pictured when they told me (long, pointed face, pointy ears) and I've been creeped out by those dogs ever since - and a body that's relatively human (skin tone, legs etc.). I want to say there was something else unique about them but I can't remember it all now, they walked on two legs and there was something yellow about them (maybe eyes?), the color just sticks out in my memory. There was a lot of detail they told me which is why I felt they were honest, and whatever they saw was most definitely NOT human.

I was so concerned after hearing about it that after I got off work I called my dad (who has dealt with the paranormal before) to see what he thought about it, and he didn't really give me much input, he thought it was their imagination's. It could be, but at the time I thought maybe they could be some kind of demon.

I researched on the descriptions they gave me but never came up with anything and it always confused me.

They didn't like whatever these things were, they scared them; I don't know if they ever came into contact with the things, not as far as I know, after that summer I obviously lost contact with the kids.

I'm sure I asked if they had told their mom and dad about it, I don't think they had... I probably told them to, but I never brought it up to the parents for some reason.

It's just one of those things I'll never have an answer for and it's frustrating! Sorry if there isn't a lot of description, but if you have experienced something like this, or have ANY idea what these things could have been (I've honestly thought "Alien" at times, but I'm not a big believer on that), I'd love to hear your intake. Maybe it was just a story, but I truly feel as though it were not, I believe whatever they saw was real.