Raid the Potions storeroom

You sneak down the corridor leading to the Dungeons, hoping you’ll find them deserted. When you checked it last, the Marauder’s Map showed that Professor Snape was in his personal quarters and no one else was in the area, but you haven’t had the chance to look at it for some minutes. Cautiously, you peak around the corner and see, to your annoyance, that since you crept from the Entrance Hall, some Slytherins have left their Common Room and are loitering outside its door.

You curse yourself and wonder why you didn’t bring your Invisibility Cloak. Crouching low and out of sight, you observe the Slytherins. You hear their voices float down the corridor and groan as you recognise them. Your bad luck is even worse than you thought! Rather than being a group of first years, you recognise some of the Slytherins from your year. In the centre of the group, you see Malfoy’s pale head.

You open your bag and look through it for something that may help you. Other than a few textbooks, you have a lone Dungbomb you had bought the previous time you had been at Hogsmeade. Your only other option is to cast a Disillusionment Charm and try to sneak through the crowd of Slytherins.