This happened about a month ago and it was another lucid dream just out of the blue.

It started out in a forest and I was standing in front of this Pro Wrestler named JBL (Had no idea why he was in my dream.) I started to fight him but he was just way too strong. He pushed me to the ground and I stood up and he was gone. I turn around and it's totally dark out and there is a bridge in front of me and on the other side, about 15 feet away, is this tall guy in a hockey mask with a machete. For some random reason, I plugged my nose and tried to breathe through it and I could and I realized I was dreaming. I didn't become excited. Instead, I felt this strong feeling that I needed to defeat this guy. The first thing I try, like I've done in my past 2 lucids, is try to fire a Kamehameha (It's the only thing I know that can deal a lot of damage to a person. Just ask Cell.) I try firing it but it doesn't work. Then I pull my hands back and try firing energy blasts at him but again, it doesn't work. He starts walking towards me at a fast pace. He slashes at me and it hits me but I feel no pain. It was pretty vivd too. I jump to kick him, but I jump at an immense height and end up dropkicking him across the bridge again. The last thing I remember was me and him rolling on the ground duking it out. When I woke up, I actually jumped out of bed in an instant and was saying "I did it!".
There is my lucid but now for a question. I have had a lucid dream once a month for the past 3 or 4 months out of no where. I Wasn't thinking about lucid dreaming or anything like that. Why does this happen? Thank you.