Seven friends once pulled this at my college cafeteria.
One put a hot water bottle filled with pea soup down his chest; he sat at the head of a table, with the other six friends sitting along the sides.
When the cafeteria was pretty full of people, he made a loud noise (to attract attention), stood up, bent over and squeezed his chest.
This caused a huge gush of green liquid to spew all over the table; the other six immediately began to eat this green liquid.
I think a lot of food went uneaten that night.
