Where you put small object someone's door making a lot of noise, and the target very confused. When the person says something, you walk to a hiding place close to the door. When they bend down to grab the CD, you jump out and fart in their face
The circle prank is a multistage capacity test that gets more difficult as is continues
You put a small object under the door of a room someone is in. Then you bang the object to make the person come out of the room. Then when the person comes out you jump out and fart in their face.
The circle prank went horribly wrong when I started instead of farted.