<human>: When I was nine years old, I was left home alone with my sister. I can't remember exactly what happened, but something had startled me that was outside the house before my parents left. My sister knew this and being the wonderful sister she is, decided to scare me. I was on  the computer in a room where the computer was positioned close to a window. She snuck outside and beat on the window, making me scream and run to my room. She came back inside the house, laughing hysterically. I was pissed, as she knew I was already on edge, so I decided to get her back. 

My sister called her boyfriend to laugh about and she walked into her bathroom for a moment. I took this opportunity to crawl under her bed.

When she walked back into her room, she asked her boyfriend what the most terrifying thing to him was. He answered and then I can only assume that he asked her the same question. Her answer was this, "Probably if someone grabbed me from underneath my bed and pulled me under."

At this point I was having a hard time holding back laughter. She was sitting on her bed with her feet on the floor. So, I did what any little sister seeking revenge would do. I grabbed her ankles, screamed as loud as I could and yanked her feet under the bed. She screamed and ran away while I laid under the bed, laughing my ass off.

Can you give me a shortened version of the text?
<bot>: Sister scared me, I ran under her bed seeking revenge, she told her boyfriend that being pulled under the bed was her worst fear, I took the opportunity to scare the shit out of her.