Pillow prank

So my friend and I know how much my grandpa loves to tease us. One day we were together and we made it look like somebody was under the blanket and trying to hide. We set up pillows in the shape of a person and even put one of my shoes sticking out from the end. When my grandpa got home from fishing, I acted all suspicious (on purpose, the acting suspicious part is part of the prank) and stuck around the area of the pillows and blankets. While I was doing that my friend was hiding and getting a good veiw of the scene. My grandpa realized there was something going on, but (like planned), he had the wrong idea. He thought my friend was actually under the blankets and she was trying to hide from him. So, he went and sat on the blankets (and like he always does when someone is on the couch, he was going to act like he didn't realize they were there even when he sat on them). Man was he in for a suprise when the blanket just sank down underneath him!! (They sank down because of the pillows instead of the person underneath)