Some teenagers in New York dressed up in hazmat suits with gloves and masks, and rode the subway while holding a plastic container with a mysterious liquid inside.
To complete the prank, the container had WARNING stickers on it. The liquid was Kool-Aid, but they didn’t tell anyone. When the time was right they spilled it on the floor . . . and after people freaked out they yelled “It’s a prank. It’s a prank.”