Entertain, and it’s a story but it’s somewhat dramatic in how it tells it. I’d lean more towards story.
True because you need to explain what you are writing about and then dive into your research writing.
A slimy blue thing was in my room.
I grabbed my cat, and looked down at my mat. It was so hard to sleep, so I got up and treaded on my feet. The creature was odd looking. It looked like a pile of pigs mud, but even more gooey and liquidized. This was the weirdest thing I have ever seen in my life. Then, my cat splashed the monster, so I went and reached to turn on my light. I felt silly for having a fright, for it was just my slime that my cat spilled water that made me feel grime.