You had never did such a prank before...

You tainted The Marauders' drinks with polyjuice potion and they all turned into James. The four James came up to you, growling. "WHAT DID YOU DO?" James(I mean Sirius) yelled at you. "Nothing, Black" You replied and James(Remus) growled and James(Peter)'s face was angry. The real James was just laughing at his friends.