The Vacuum Tool is the third of 10 prizes in the Treehouse of Horror XXIV Event. You need to collect 1,250 to unlock it.
To use, click on the Ghost icon in the top-right corner and select the second image/icon down, then simply apply pressure with your finger on the screen to activate (may require multiple attempts in different spots for it to work). This will only work on Ghosts, and not Gremlins and haunted buildings. It will also only work in your Springfield and not in neighbour's towns.
|“||Equip your new tool and suck up some Ghosts!||”|
— In-game announcement