After trying for about a few months now, I've always been able to realize I was in a dream, but I would usually wake up immediately. Last night I realized I was awake, and immediately started spinning, which somehow kept me in the dream state for longer. I woke up right after I stopped spinning, but quickly fell back asleep. Then, I entered a semi-lucid dream. I did not create the environment, but I recognized it as from another dream in my childhood. I was able to create a staircase and a door, and from there things got weird. I don't know if I did it on purpose, but I'm sure I did, since I've always wanted to have a nightmare that scared me. The door disappeared, but the doorway remained. Out from it crawled Slender Man (why I chose him, I don't know why, but it was probably the first thing that came to mind). He grabbed my leg and pulled me into the abyss, where I awoke. It was my first time actually controlling aspects of my dream, and it was awesome.