Hope you enjoy! This is my theory of the great mushroom war. :)
I was walking with my mother outside. Then, we heard a huge explosion. Black smoke filled the air. We were coughing and I was crying. 2,000 warriors emerged out of a tank and ran after our kingdom. I remember dad trying to fight them off, but he got locked into the Nightosphere. Mom was crying, but desperately trying to hide it. She took out her emergency pod, and locked me in it.
When I woke up, I was astonished. Everything was completely destroyed. I looked around for my mom. I gasped at what I saw and started crying insanely. My mother's dead, bloody body was before me. I reached down and tried to save her, I tried. But I couldn't bring back the dead. I saw a note in her pocket. I read it. "Marceline, I will always love you. If I am locked into the Nightosphere, I will still love you. If daddy dies, I will still love you. If I die, I will be looking out for you and still loving you." I began to cry again when he showed up. He wiped away my tears and gave me Hambo. We played together and we laughed together. I was never alone until Simon's hair started to turn white, and his skin blue. He started being rude, but immediately apologized. He left me alone. He forgot. He doesn't care. Or does he?