I think I met my spirit/dream guide.

This was my second lucid dream using the MILD method. As I am still a beginner my lucidity don’t last very long. I visualized a futuristic city to start my lucid adventure. It started off with me falling onto a moving train and then I shouted “I’m dreaming”. I saw some power from within me explode onto the setting and colors just came to life. I demanded the train to stop and then I felt my lucidity going away. I looked down and rubbed my hands together and it felt like my powers came back. When I looked up again I was at the bottom of a waterfall with blue silvery fish. I then said “Spirit guide I need you”. I read somewhere when someone appears and you ask “are you really my spirit guide guide?” and they answer yes 3 times its the real deal. My spirit guide was a grey static silhouette with no face or features or clothes, just grey but I knew it was a male. I was about to ask how long do I have left till I wake up but then I woke up.

I was very happy that I had a lucid dream again.

Questions:
Was he really my spirit guide?
Why was he grey all over?
Why did I teleport to the bottom of a waterfall that I had no intentions of going to?
What was that explosion when I first knew I was dreaming?

Thanks

Only you can really answer whether or not you feel it was a spirit guide.

As for the colour, spiritual beings (and I include us in that) all have a colour, it is who they/we are. Physical forms will vary, because they can appear in what ever form they wish. I would suggest trying to meet them again, ask him these questions.